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Genotoxicity of tobacco and alcohol on human oral mucosal cells

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Chewing and smoking of tobacco as well as drinking of alcohol have been reported as the risk factors for oral cancer. The high incidence of oral cancer in India and gradual increase of oral cancer patients at the Out Patient Department of Acharya Harihar Regional Cancer Center (AHRCC) Cuttack, Odisha (the only Government Hospital of the state dedicated for the treatment of the cancer patients) prompted us to undertake this study. In this hospital-based case-control study, the genotoxic effect of tobacco and alcohol was evaluated through micronucleus test. The percentage of micronucleated cells were recorded to be the highest in chewer-smoker-alcoholics group (2.86 in males and 3.35 in females) and the least in smokers' group (0.68 in males and 0.65 in females). The values were found to be statistically significant at 1% level of confidence (Z-test). But, the occurrence of micronucleated cells in higher percentage in non-addicted cancerous group (1.23 in males and 1.20 in females) than the single addicted groups (such as chewers, smokers and alcoholics) indicate the causes of genetic susceptibility followed by oral unhygienic condition and modern life style in food pattern among the people of Odisha. Therefore, it needs special attention for which further investigation is suggested.
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European Journal of Experimental Biology, 2013, 3(2):503-514
ISSN: 2248 –9215
CODEN (USA): EJEBAU
503
Pelagia Research Library
Genotoxicity of tobacco and alcohol on human oral mucosal cells
Abhimanyu Mohanta
1
, Prafulla K. Mohanty
1
and Gadadhar Parida
2
1
P.G. Dept. of Zoology, Utkal University, Vani Vihar, Bhubaneshwar, Odisha, India
2
Dept. of Oncopathology, Acharya Harihar Regional Cancer Center (AHRCC), Cuttack, Odisha, India
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ABSTRACT
Chewing and smoking of tobacco as well as drinking of alcohol have been reported as the risk factors for oral
cancer. The high incidence of oral cancer in India and gradual increase of oral cancer patients at the Out Patient
Department of Acharya Harihar Regional Cancer Center (AHRCC) Cuttack, Odisha (the only Government Hospital
of the state dedicated for the treatment of the cancer patients) prompted us to undertake this study. In this hospital-
based case-control study, the genotoxic effect of tobacco and alcohol was evaluated through micronucleus test. The
percentage of micronucleated cells were recorded to be the highest in chewer-smoker-alcoholics group (2.86 in
males and 3.35 in females) and the least in smokers’ group (0.68 in males and 0.65 in females). The values were
found to be statistically significant at 1% level of confidence (Z-test). But, the occurrence of micronucleated cells in
higher percentage in non-addicted cancerous group (1.23 in males and 1.20 in females) than the single addicted
groups (such as chewers, smokers and alcoholics) indicate the causes of genetic susceptibility followed by oral
unhygienic condition and modern life style in food pattern among the people of Odisha. Therefore, it needs special
attention for which further investigation is suggested.
Key words: Genotoxicity, oral cancer, buccal mucosa, exfoliated cells, cytosmears, addiction, micronucleus.
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INTRODUCTION
Oral cancer is one of the ten most common cancers as stated by World Health Organization (WHO) and each year
5,75,000 new cases and 3,20,000 deaths occur world-wide [1]. In India, oral cancer is a major health problem which
accounts for 30-40% of all cancers diagnosed and is the sixth common cause of death in males and seventh in
females [2]. In Orissa, tobacco related oral cancer is found to be very common which may be due to the chewing
habit of different forms of tobacco (oral snuff, khaini, betel, betel-quid, gutkha and paan masala) and smoking of
bidi (a type of native cigarette prepared from dried tobacco leaves powder, rolled in a piece of tembhurni leaves),
cigarettes etc. Registration of more number of late-stage oral cancer patients for first time treatment in the Out
Patient Department (OPD) of Acharya Harihar Regional Cancer Center (AHRCC), Cuttack, and Odisha has
prompted us to undertake this study. The present investigation aims at the study of genotoxicity of tobacco and
alcohol on the buccal mucosa of oral cancer patients and to assess the relevance of micronucleus test in the early
detection of oral cancers.
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MATERIALS AND METHODS
2.1 Collection of samples
Exfoliated cytosmears were collected by scraping from the clinically diagnosed 136 patients suffering from
precancerous lesions and oral squamous cell carcinoma (OSCC) at the Out Patient Department (OPD) of Acharya
Harihar Regional Cancer Center (AHRCC), Cuttack, Odisha, during May 2007-May 2009. Smearing was done on
the pre-cleaned-coded microslides and the slides were fixed in aceto-alcohol (1:3) fixative, immediately. Two slides
were smeared and prepared from each affected sites of the patient. Prior to the collection of samples, case-history of
the patients related to their age, sex, food, habits, oral hygiene and occupation were asked and recorded for detail
analysis. A parallel set of 136 samples were also collected from the non-addicted and non-cancerous individuals
from different regions of Odisha which are called as control group.
2.2 Staining protocol and scoring of micronuclei
The wet fixed smears were stained by adopting Papanicolaou’s staining protocol and counter-stained with Giemsa’s
solution. One thousand cells were screened and the micronucleated cells were scored from each stained sample
following standard criteria [3,4,5]. Although more than one micronuclei were observed in oral squamous cells
(Figs.1-4), the scored elements were MNCs and not the number of micronuclei [6]. Photomicrographs were taken
out as the supporting evidence.
2.3 Statistical analysis
Findings were statistically analyzed, interpreted and correlated with the age group, sex and degree of pathogenicity.
Test of proportion (Z-test) was followed and the critical ratio (Z-value) was calculated for the test of
significance. The following formula was used for the calculation of Z-value [7].
Z
2
22
1
11
21
nqp
nqp
IpIp
+
=
Where, p
1
= Proportion of the MNCs in control group (sample-I), p
2
= Proportion of the MNCs in affected
group (sample-II), q
1
= 1-p
1
(in case of percentage, 100-p
1
), q
2
=1-p
2
(in case of percentage, 100-q
2
), n
1
=size of
the sample-I, n
2
= size of the sample-II,
and
2
22
1
11
nqp
nqp +
= Standard error of difference between the two sample proportions.
The observed Z-values for normal distribution at 5% and 1% level of confidence are 1.96 and 2.576
respectively.
RESULTS
The general characteristics of the oral cancer cases such as age group, food habit, addiction, occupation and oral
hygiene were taken into account (Table.1). Out of 136 patients, 82 (60.3%) were males and 54 (39.7%) were
females. More number of oral cancer patients were observed in 50-69 years of age group than the other two groups.
The highest percentages of the OSCC patients were recorded to be 41.5 and 66.7 in males and females respectively,
whereas, the lowest percentages were found to be 18.3% in males and 12.9% in females in the age group of 70-89
years.
Basing on the food habits of the patients, 92.7% were non-vegetarian who prefer to take meat, fish and eggs while
7.3% were vegetarian. In non-vegetarian group, the percentage of males was more (96.3%) than the females
(87.1%). On the contrary, the percentage of females is more (12.9%) than the males (3.7%) under vegetarian
category.
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It is reported that out of 136 oral cancer patients, 126 (92.6%) were addicted to different forms of tobacco and
alcohol for more than 15 years, while 10 (7.4%) were non-addicted completely. The addicted individuals were
categorized into five different groups, such as chewers, smokers, alcoholics, chewer-smokers and chewer-smoker-
alcoholics. The chewers’ group having 43 patients was recorded to be the highest (31.61%) and the smokers’ group
having 11 patients was found to be the lowest. All the patients were reported to brush their teeth at least once in a
day, but in different ways.
Table 1 Sex-wise general characteristics of the oral cancer cases
No Characteristics Male Female Total
Number of cases % Number of cases % Number of cases %
1
Age group
30-49
50-69
70-89
33
34
15
40.2
41.5
18.3
11
36
07
20.4
66.7
12.9
44
70
22
32.4
41.4
16.2
2 Food habit
Vegetarian
Non-vegetarian
03
79
3.7
96.3
07
47
12.9
87.1
10
126
7.4
92.6
3
Addiction
Chewers
Smokers
Alcoholics
Chewer-smokers
Chewer-smoker- alcoholics
Non-addicted
23
09
12
24
08
06
27.8
10.9
14.7
29.5
9.8
7.3
20
02
18
04
06
04
37.02
3.7
33.3
7.4
11.2
7.4
43
11
30
28
14
10
31.61
8.08
22.05
20.58
10.29
7.35
4
Occupation
Labourer
Farmer
Teacher
Others(heterogenous)
17
08
15
42
20.7
9.7
18.3
51.3
22
Nil
03
29
40.7
Nil
5.6
53.7
3.9
08
18
71
28.7
5.8
13.2
52.3
5
Oral hygiene: Tooth brushing
Plant stick only
Plant stick+ toothpaste/powder
Tooth brush with paste/powder
36
15
31
43.9
18.2
37.9
26
09
19
48.1
16.6
34.3
62
24
50
45.5
17.6
36.9
Source: Primary data.
The genotoxicity of tobacco and alcohol on buccal mucosal cells of human being has been evaluated through
micronucleus test (MNT). Because, MNT is one of the most widely applied short term test used in genetic
toxicology and has become one of the most important tests implemented by the regulatory authorities of
different countries to evaluate mutagenicity of, and sensitivity to, xenobiotics [8, 9]. Since, the formation of
micronuclei in the eukaryote cells is an end point of chromosomal damage or segregation errors [10], the
presence of micronuclei reflects a genotoxic exposure. The micronucleated cells were observed to have either
one or more than one micronuclei (Figs.1-4). In this present study, the scored elements were micronucleated
cells and not the number of micronuclei [3, 4, 6].
The frequencies of micronucleated cells (MNCs) in control and addicted cancerous and non-addicted
cancerous groups exhibit an increasing order from lower to higher age groups (Table 2). In control group, all
of 82 males and 54 females were non-addicted and non-cancerous individuals. In the age group of 30-49, 50-69
and 70-89 years, the number and percentage of MNCs scored from 33, 34 and 15 males were 07, 09 and 06 and
0.021, 0.026 and 0.068 accordingly. The number and frequencies of MNCs from 11, 36 and 07 females were
scored to be 02, 07 and 02 and 0.018, 0.019 and 0.028 in 30-49, 50-69 and 70-89 years of age groups,
respectively (Figs.5-8). The mean percentage was calculated to be 0.026 in males and 0.020 females
respectively.
The MNCs in chewers’ group (Table 2) were scored to be 141, 99 and 109 from 11,07 and 05 samples of male
individuals having the percentage 1.28, 1.41 and 2.18 in 30-49, 50-69, 70-89 years of age group respectively.
The mean percentage of MNCs in male was calculated to be 1.51. The scoring of MNCs in females were
recorded to be 63, 137 and 82 from 06, 11 and 03 females with the percentage of 1.05, 1.25 and 2.73 in the age
group of 30-49, 50-69 and 70-89 years, respectively having the mean percentage 1.41. In comparison with the
control group, the critical ratios were found to be 18.409 in males and 16.628 in females and are thus highly
significant (p < 0.01).
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Fig.1 Monomicronucleated oral squamous cell (Giemsa’s stain x400)
Fig.2 Bi-, tri- and tetramicronucleated condition of oral squamous cells (Giemsa’s stain, x400)
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Fig.3 Anisonucleated octamicronucleated condition of an oral squamous cell (Papanicolaou’s stain, x 400)
Fig.4 Pentanucleated trimicronucleated condition of an oral
squamous cell (Papanicolaou’s stain, x 400).
The number and frequencies of micronucleated cells in smokersgroup were observed to be 12 and 0.60 in 02
males in the age group 30-49 years. No female cases were reported to register in this age group. In 50-69
years, 32 MNCs from 05 males and 13 MNCs from 02 females having percentage 0.64 and 0.65 were scored
respectively. In 70-89 years, no female cases were reported and hence 28 MNCs were enumerated from 02
males having the percentage 0.90. Thus, the mean percentage of MNCs in males and females were calculated
to be 0.680 and 0.65 respectively. In smokersgroup, the critical values were calculated to be 7.53 and 3.504
in males and females respectively (Figs.5-8). Since, these values are greater than the normal observed value
(Z=2.576), it indicates that smoking has a genotoxic effect on buccal mucosa for the development of oral
carcinoma.
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In alcoholic group, 24, 40 and 28 numbers of MNCs were calculated from 04, 05 and 03 males having the
percentage of 0.60, 0.80 and 0.93 in the age group of 30-49, 50-69 and 70-89 years respectively. The mean
percentage of MNCs in males was 0.76. The number and frequencies of MNCs in females were scored to be
22, 87, 19 and0.55, 0.725, 0.95 from 04, 12 and 02 females in 30-49, 50-69 and 70-89 years of age groups. The
mean percentage of the MNC was calculated to be 0.71 in females. The Z-values, in alcoholic groups are, thus
calculated to be 9.235 in males and 10.937 in females (Figs.5-8), which implies that alcohol has a synergistic
effect on oral mucosa in the process of micronuclei formation followed by oral carcinogenesis.
Referring to the chewer-smokers group, the MNCs were scored to be 142 from 09 males with a frequency of
1.571 per cent in 30-49 years of age group. In this age group, no MNCs were scored from the females due to
unreported female oral cancer patients. In 50-69 years of age group, 215 and 63 MNCs were scored from 12
males and 03 females. The calculated frequencies were 1.79 in males and 2.10 in females. The number and
frequencies of MNCs were reported to be 71 and 2.36 per cent in 03 males and 23 and 2.30 per cent in one
female of 70-89 year age group. The average frequencies were calculated to be 1.78 in males and 2.15 in
females. The critical ratios in chewer-smokers group were recorded to be 20.506 in males and 9.284 in females
(Figs.5-8). It signifies that both chewing and smoking of tobacco have a greater impact on oral squamous cells
than those of chewers or smokers.
The number and frequencies of MNCs in chewer-smoker-alcoholics group were observed to be very high. It
was estimated that, 86 MNCs from 04 males having 2.15 per cent frequency was calculated in the 30-49 years
of age group. Female cases were not recorded in this age group because of unreported situation. In 50-69 years,
the number and frequencies of MNCs observed from 03 males were 106 (3.53 per cent) and from 06 females,
213(3.55 per cent) respectively. No female but only 01 male was recorded in 70-89 years of chewer-smoker-
alcoholics group. The number and percentage of MNCs were found to be 37 and 3.70 in this age group
respectively. Hence, the average percentage of MNCs in males was 2.802 and in females, it was 3.55. The Z-
values in this group was calculated to be 15.20 in males and 14.772 in females and were found to be
significantly higher than the normal value (Z=2.576) at 1% level of significance (Figs.5-8).
In non-addicted cancerous group, the numbers of MNCs were reported to be 17, 34 and 23 in 03, 02 and 01
male and having the percentage 0.56, 1.70 and 2.30 in 30-49, 50-69 and 70-89 year of age groups respectively.
The mean percentage of MNCs in males was calculated to be 1.23. In females, 07, 26 and 15 MNCs were
reported from 01, 02 and 01 females with the frequencies of 0.70, 1.30 and 1.50 in 30-49, 50-69 and 70-89
years of age group. In females, the mean percentage of the MNCs was calculated to be 1.20. The Z-values, in
non-addicted cancerous group were calculated to be 8.454 in males and 6.849 in females and were found to be
significant (p<0.01). Though, very few non-addicted individuals (06 males and 04 females) suffer from oral
carcinoma, the existence of significant number of micronuclei in their exfoliated samples were, probably, due
to genetic susceptibility, oral unhygienic, modern life style in food habit or even multifactorial effect.
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Table 2 Frequencies of micronucleated cells (MNCs) in control, addicted and non-addicted cancerous groups
No Group Age group in
years Number of Samples screened Number of cells MNCs scored Percentage of MNCs Mean percentage of MNCs Critical ratio
(Z-value)*
Male Female Male Female Male Female Male Female Male Female
1 Control 30-49 33 11 07 02 0.021 0.018 0.026 0.020 - - 50-69 34 36 09 07 0.026 0.019
70-89 15 07 06 02 0.068 0.028
Total 30-89 82 54 22 11 0.026 0.020 0.026 0.020 - -
2. Chewers 30-49 11 06 141 63 1.28 1.05 1.51 1.41 18.409* 16.628* 50-69 07 11 99 137 1.41 1.25
70-89 05 03 109 82 2.18 2.73
3 Smokers 30-49 02 Nil 12 Nil 0.60 Nil 0.68 0.65 7.53* 3.504* 50-69 05 02 32 13 0.64 0.65
70-89 02 Nil 18 Nil 0.90 Nil
4. Alcoholics 30-49 04 04 24 22 0.60 0.55 0.76 0.71 9.235* 10.973* 50-69 05 12 40 87 0.80 0.725
70-89 03 02 28 19 0.93 0.95
5. Chewer- Smokers 30-49 09 Nil 142 Nil 1.57 Nil 1.78 2.15 20.506* 9.284* 50-69 12 03 215 63 1.79 2.10
70-89 03 01 71 23 2.36 2.30
6. Chewer- smoker-
alcoholics
30-49 04 Nil 86 Nil 2.15 Nil 2.86 3.55 15.20* 14.772* 50-69 03 06 106 213 3.53 3.55
70-89 01 Nil 37 Nil 3.70 Nil
7. Non-addicted cancerous 30-49 03 01 17 07 0.56 0.67 1.23 1.20 8.454* 6.849* 50-69 02 02 34 26 1.70 1.30
70-89 01 01 23 15 2.30 1.50
Total 30-89 82 54 1234 770 1.504 1.425 1.504 1.425 34.472* 27.353*
Source: Primary data. * Significant at 1% level (p<0.01) of confidence, where tabulated figure of Z=2.576.
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Fig.5 Age group and addiction-wise enumeration of micronucleated cells
Fig.6 Percentage of micronucleated cells in different age groups of normal,addicted and non-addicted cancerous groups
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Fig.7 Age group and sex-wise mean percentage of micronucleated cells in control, addicted and non-addicted cancerous groups
Fig.8 Critical ratios(Z-values) in addicted and non-addicted cancerous groups
Looking into the above analysis, it was observed that the number and frequency of MNCs were in increasing
trends along with the increase of age, in both control and addicted groups. It has also been observed that the
mean frequencies of MNCs were recorded to be the lowest (0.68 in males and 0.65 in females) in smoker
group and the highest (2.86 in males and 3.55 in females) in chewer-smoker-alcoholic group. But, the
frequency of MNCs in non-addicted cancerous group (1.23 per cent in males and 1.20 per cent in females) was
found to be more than those of smokers (0.68 per cent in males and 0.65 per cent in females) and alcoholics
group (0.76 per cent in males and 0.71 per cent in females) which needs further investigation. The present
study corroborates the earlier findings of [11, 12, 13].
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Micronucleated cells are, no doubt, a type of pleomorphic diagnostic cell in oral squamous cell carcinoma
(OSCC) having its own significance. Formation of micronuclei in the epidermal squamous cells is a clear
indication of genetic alteration in these cells. In the present study, it has been found that tobacco and alcohol
are not the only factors of micronucleation but some other causes responsible for this may be genetic,
environmental, biological and physical factors. During this investigation, it was established that longer the
duration of abuse of tobacco and alcohol, greater was the number of MNCs. It has also been proved through
the test of significance that chewing and smoking of tobacco and drinking of alcohol enhance the rate of
formation of micronuclei along with other cytological atypias followed by oral squamous cell carcinoma
(OSCC).
DISCUSSION
Micronuclei are either acentric chromosome fragments or whole chromosome lagging in the normal karyokinesis [4,
6, 14]. These laggards or fragments of chromosomes are excluded from the post-mitotic daughter cells and form
nuclei. Thus, these micronucleated cells (MNCs) are represented either chromosomal breakage (clastogenicity) or a
failure in the spindle fibre mechanism (tubragenicity) during cell division.
The induction of micronucleus in oral mucosal cells seems to be due to the presence of genotoxic agents in the
tobacco and alcohol. According to Livingstone et al. [15] , saliva soluble compounds present in tobacco could
diffuse into the basal cell layer and disturb the reproductive mechanism of the underlying proliferating cell
population, thereby bringing about genotoxicity and micronuclei formation. Nagler and Dayan [16] have also
reported that the interaction between redox active metals in saliva and the low reactive free radicals during chewing
and smoking of tobacco enhance the potency of genotoxicity. The result may be that saliva loses its antioxidant
property and instead, it becomes a potent pro-oxidant milieu. This leads to oral mucosal cells to be an aberrant one
and promotes for oral carcinogenesis.
It has also been reported that chewing of betel-quid produces reactive oxygen species (ROS) that have multiple
detrimental effects upon the oral mucosa. The production and release of ROS occurs under alkaline condition,
during the auto-oxidation of areca-nut polyphenols in the saliva of betel-quid-chewers [17] . Prokopczyk et al. [18]
have opined that , areca-nut- specific-nitrosamines along with tobacco-specific-nitrosamines (TSNA) are found to be
mutagenic, genotoxic, and carcinogenic and capable of inducing tumors in the oral cavity.
Alcohol, acting both independently as well as synergistically with smoking has been implicated in oral
carcinogenesis [19]. More importantly, alcohol may act as a solvent and enhance the penetration of carcinogens into
target tissues. In fact, alcohol (ethanol) is metabolized by an enzyme alcohol dehydrogenase and to some extent, by
cytochrome p
450
to acetaldehyde which is found to be carcinogenic [20, 21]. The growing evidences associate
increased alcohol consumption with risk of developing OSCC [22, 23]. The combined effects of tobacco use and
alcohol consumption are found to be multiplicative. Compared with persons who neither drink nor smoke, the risk of
developing OSCC is increased 80 fold in persons with the highest level of smoking and alcohol consumption [24].
Earlier reports suggest that the micronucleus test in human exfoliated oral mucosal cells provides evidence of
exposure to carcinogens and measure of degree to carcinogen exposure in the tissue from which cancer develops.
Increase in micronucleus frequency in buccal mucosal cells of tobacco and alcohol-users indicates a high risk group
of oral cancer [11, 12, 14, 25, 26]. Gandhi and Kaur [13] have reported that the mean frequency of MNCs among
paan masala chewers was 0.303±0.058 and was found to be significant when compared with the control group
(mean frequency was nil), but non-significant among the different age groups of paan masala chewers. Some authors
have described sex as an important variable in the micronucleus test [27, 28, 29], with males generally being more
sensitive than females to the induction of micronuclei [30, 31]. But, other studies have shown no sex related
differences in micronucleus test results [32, 33, 34, 35].
In the present study, the mean percentages of the MNCs were found to be significantly the highest (2.86 in males
and 3.35 in females) in chewer-smoker-alcoholics group and the lowest (0.68 in males and 0.65 in females) in
smokers group. It is also observed that, the mean percentage of MNCs was calculated to be more in chewers group
(1.15 in males and 1.41 in females) than the alcoholics group (0.76 in males and 0.71 in females). But, the recorded
percentage of MNCs in chewer-smokers group (1.78 in males and 2.15 in females) was found to be higher than the
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independent groups of chewers and smokers. The present finding indicates that the combined effect of tobacco and
alcohol is proved to be highly genotoxic to the buccal mucosal cells in both sexes. No doubt, the genotoxic effect of
smoking is observed to be the lowest, but it enhances the formation of micronuclei in the buccal mucosal cells of
human being along with the chewing of tobacco and drinking of alcohol. The percentage of MNCs in non-addicted
cancerous group was found to be more (1.23 in males and 1.20 in females) than the chewers, smokers and alcoholics
groups, but less than the mixed groups, which may be due to oral unhygiene, modern life style (mostly consuming
fast food) and genetic susceptibility, which needs special attention for further research.
CONCLUSION
The present investigation was a hospital-based case-control study. The findings indicate that the combined effect of
tobacco and alcohol has shown more genotoxicity than the single use on the buccal mucosal cells. The formation of
more number of micronucleated cells in chewer-smoker-alcoholics group followed by in chewer-smokers than other
addicted (chewers, smokers and alcoholics) groups has proved the genotoxic effect of tobacco and alcohol on oral
mucosal cells. The results also support the facts of earlier findings that longer the addiction, more the number of
micronuclei formation in oral mucosal cells. Furthermore, higher percentage of micronucleated cells in non-addicted
oral cancer patients has proved the micronucleated cells to be an onco-indicator and micronucleus test to be the
simplest tool for the test of genotoxicity as well as for the early detection of cancer of the oral cavity.
Acknowledgements
Authors are thankful to the Head, P.G. Dept. of Zoology, Utkal University, Vani Vihar, Bhubaneshwar, Orissa for
providing laboratory and library facilities; to the Director, Acharya Haihar Regional Cancer Center (AHRCC),
Cuttack, Orissa for permitting us to collect samples from the oral cancer patients and also for providing library and
laboratory facilities and one of us (AM) is grateful to the University Grants Commission (UGC), New Delhi for
awarding UGC Research Fellowship to carry out the project work.
REFERENCES
[1] Halder, A., Chakraborty, T., Mandal, K., Guru, P.K., Das, S., Roychoudhury, R., Ghosh, A.K., De, M., Int. J.
Hum. Genet., 2004, 4(4), 257-260.
[2] Bhattacharjee, A., Chakroborty, A. and Purkayastha, P., Ind. J. Otolaryngol. Head and Neck Surg., 2006,
58(1), 15-19.
[3] Schmid, W., Mutat. Res.,1975, 312, 9-15.
[4] Schmid, W.,The micronucleus test for cytogenetic analysis. In Hollander A (Ed) Chemical Mutagens, Vol-
4(Plenum Publishing Co., New York), 1976, 31-53.
[5] Fenech, M., Chang, W.P., Kirsch-Volders, M., Holland, N., Bonassi, S. and Zeiger, E. Mutat. Res., 2003,
534 (1-2), 65-75.
[6] Schmid, W. Micronucleus test: an in vivo bone marrow method. In Hsu TC (Ed) Cytogenetic Assays for
Environmental Mutagens, (Oxford and IBH Publishing Co., New Delhi), 1982, 221-229.
[7] Kothari C.R. Research Methodology: Methods and Techniques, Second Edition, (Wishwa Prakashan, New
Delhi, India), 1997, 223-267.
[8] Anonymous, Mammalian erythrocyte micronucleus test. In Guidelines for testing of chemicals n.474,
(Organization for Economic Operation and Development (OEOD), Paris), 1997, 1-10.
[9] Anonymous, Mammalian erythrocyte micronucleus test. In Health Effects Test Guidelines OPPTS 870.5395,
(Environmental Protection Agency, USA), 1998, 1-12.
[10] Geard, C.R. and Chen, C.Y., Radiat. Res., 1990, 124, 856-861.
[11] Stich, H.F., Stich, W. and Parida, B.B., Cancer Lett., 1982, 17, 125-134.
[12] Ghosh, U.R. and Parida, B.B., Ind. J. Cancer, 1995, 32(3), 95-99.
[13] Gandhi, G. and Kaur, R., Human Ecology (Special Issue), 2000, 9, 221-228.
[14] Parida, B.B. and Ghosh, U.R., Proc. Natl. Acad. Sci. India, 1992, 62(B), 31-34.
[15] Livingstone, G.K., Reed, R.N., Olson, B.L. and Lockey, J.E., Environ. Mol. Mutagen, 1990, 15, 136-144.
[16] Nagler, R. and Dayan, D., The dual role of saliva in oral carcinogenesis, Oncology, 2006, 71(1-2), 10-17.
[17] Nair, U., Obe, G., Nair, J., Maru, G.B., Bhide, S.V., Pieper, R. and Bartsch, H., Mutat. Res., 1987, 261, 163-
168.
[18] Prokopczyk, B., Revenson, A., Bertinato, P., Brunnemann, K.D. and Hoffmann, D., Cancer Res., 1987, 47,
407-471.
Abhimanyu Mohanta
et al Euro. J. Exp. Bio., 2013, 3(2):503-514
_____________________________________________________________________________
514
Pelagia Research Library
[19] Anonymous, Alcohol Drinking. IARC Monograph on the evaluation of carcinogenic rises of chemicals to
human, (International Agency for Research on Cancer (IARC), Lyon, France), 1989, 416.
[20] Blot, W.J., Cancer Res., 1992, 52, 2119-2123.
[21] Harty, L.C., Capsaraso, N.E., Hayes, R.B., Winn, D.M., Bravo-Otero, E. and Blot, W.J., J. Natl. Cancer Inst.,
1997, 89, 1698-1705.
[22] Petti, S. and Scully, C., Oral Oncol., 2005, 41(8), 828-834.
[23] Warnakulasuriya, S., Parkkila, S., Nagao, T., Preedy, U.R., Koivisto, H. and Niemela, O., J. Oral Pathol. Med.,
2008, 37(3), 157-165.
[24] Scully, C., Cancers of the oral mucosa. Elsevier, Science Direct, 2010.
[25] Heddle, J.A. and Salamone, M.F., The micronucleus assay. In Stich HF and San RHC (Ed) Short-term Tests for
Chemical Carcinogens, (Springer-Verlag, New York), 1981, 234.
[26] Heddle, J.A., Hite, M., Kirkhart, B., Mavournin, K., MacGregor, J.T., Newell, G.W. and Salamone, M.F.,
Mutat. Res., 1983, 123, 61-118.
[27] Fenech, M., Niville, S. and Rinaldi, J., Mutat. Res., 1994, 313, 203-207.
[28] Zuniga-Gonzalez, G., Torres-Bugarin, O., Ramos-Ibarra. M.L., Zamora-Perez, A., Gomez-Meda, B.C.,
Ventura-Aguilar, A., Ramos-Mora, A., Ortiz, G.G., Alvarez-Moya, C., Ontiveros-Lira, D. et al., Environ. Mol.
Mutagen, 2001a, 37, 173-177.
[29] Zuniga-Gonzalez, G., Torres-Bugarin, O., Zamora-Perez, A., Gomez-Meda, B.C., Ramos-Ibarra, M.L.,
Gonzalez-Rodriguez, A., Lunna-Aguirre, J., Ramos-Mora, A., Ontiveros-Lira, D. et al., Mutat. Res., 2001b, 494,
161-167.
[30] Hayashi, M., Sofuni, T. and Ishidate, M., Mutat. Res., 1982, 105, 253-256.
[31] Anonymous, Mutat. Res., 1988, 559, 1-9.
[32] Vanparys, P., Vermeiren, F., Sysmans, M. and Temmerman, R., Mutat. Res.,1990, 244, 95-103.
[33] Mudry, M.D., Labal de Vinuesa, M.L., Gonzalez Cid, M. and Larripa, I., Mutat. Res. 1994, 305, 127-132.
[34] Gimmler-Luz, M.C., Rodrigues de Andrade, H.H. and Tozzo Marafon-Bayer, A., Braz. J. Genet., 1997, 20,
247-252.
[35] Abrevaya, X.C., Carballo, M.A. and Mudry, M.D., Genet. Mol. Biol., 2007, 30(4), 1139-1143.
... The MN test on human exfoliated cells provides the evidence of exposure to carcinogens and measures the degree of carcinogenic exposure in the tissue from which cancer develops. Increase in MNi frequency in buccal mucosa of tobacco and alcohol users indicates a high risk group for oral cancer [30][31][32][33][34]. Mohanta et al. [35] have reported that genotoxicity of tobacco and alcohol triggers the induction of MNi and MNCs in the oral mucosa and their combined effect was found to be more genotoxicity than the single use on the buccal mucosal cells. The formation of more number of MNCs in chewer-smoker-alcoholics group followed by in chewer-smokers than single addicted (chewers, smokers and alcoholics) groups has proved the potentiality of genotoxic effect of tobacco and alcohol on oral mucosal cells. ...
... The formation of more number of MNCs in chewer-smoker-alcoholics group followed by in chewer-smokers than single addicted (chewers, smokers and alcoholics) groups has proved the potentiality of genotoxic effect of tobacco and alcohol on oral mucosal cells. The results also support the facts of earlier findings that longer the addiction, more the number of MNi formations in oral mucosal cells [35]. ...
Article
Full-text available
Objective: Micronucleated cells (MNCs) are a special type of cytological atypia observed in the exfoliated cytosmears of control and oral neoplasm cases. Conflicting opinions related to the size of micronuclei (MNi) in oral epithelial cells prompted us to undertake for a complete resolution. Therefore, the objectives of the present study are to evaluate the cytopathogical importance of oral micronucleated cells (MNCs) and to bring about a comprehensive conflict resolution on account of the size of the micronucleus (MN) with respect to its parent nucleus (PN) through morphometric analysis. Methodology: In a hospital-based Case-Control study, exfoliated cytosmears were collected from the age group, sex and oral sites- matched 272 subjects. Smears were fixed in 1:3 aceto alcohol. Out of two smearing slides, one was stained with Papanicolaou’s stain and the other was stained with Giemsa’s stain. Standard protocol was followed for scoring of MNCs. Cytomorphometry and photomicrography was done by using computer assisted Bio-Catalyst Cat Cam 1.30 microscope camera. Palaentological Statistics (PAST), Version 2.17.was used for statistical analysis. Result: Significantly higher percentage (z<0.01) of pleomorphic MNCs were observed in cancer affected group than the normal counterpart. Nuclear-Cytoplasmic (N/C) ratios of the MNCs were found to be in increased state (1:12.5) in both sexes as compared to the normal ones (1:34.5 in male and 1:34.4 in female). Interestingly, the MN/PN ratios of the MNC were calculated to be 1:8.66 in male and 1:8.56 in female. Conclusion: Due to universal occurrence, pleomorphism and increased nuclear-cytoplasmic (N/C) ratios as well as increased MN/PN ratios in both sexes, the MNCs are considered as a potential biomarker and a sensitive onco-indicator during oral carcinogenesis. Therefore, MNT is to be applied as a reliable cytogenetic tool for prognosis and diagnosis of human oral cancer. Keywords: Micronucleated cells; Micronucleus; Atypia; N/C ratio; MN/PN ratio
... Micronucleus testing (MNT) has been used to assess the genotoxicity of tobacco on human buccal mucosal cells. Because MNT is one of the most often used short-term tests in genetic toxicology and has grown to be one of the most significant assays utilized by regulatory agencies across the world to assess xenobiotic mutagenicity and sensitivity [10] . The presence of micronuclei indicates a genotoxic exposure because the production of micronuclei in eukaryote cells is the result of chromosomal damage or segregation abnormalities. ...
Article
Full-text available
Smoking cigarettes can lead to a number of health issues or fatal diseases including cancer. The numerous lethal carcinogens found in cigarettes cause DNA damage in a variety of organs. The frequency and length of exposure directly correlate with this harm. Micronuclei arise primarily as a result of genetic damage to living cells. The micronucleus (MN), a nuclear body that can easily be seen in exfoliated buccal cells, is created when chromosomes break or segregate during cell division. This study was done to estimate the DNA damage in smokers' exfoliated buccal cells. So, utilizing MN assay of exfoliated buccal cells from nonsmokers (Comparison group) and smokers with respect to duration and frequency of use, the current study was conducted to assess the genetic damage. Two groups of people were taken, 50 for smokers, and 30 nonsmokers. Results were noted, In Controls and Smokers, the mean and variance of the percentage of nuclear abnormalities overall were, respectively. (25.967±0.681), (46.240±0.700*). The results of an independent sample t-test indicated a significant difference between the means of the two groups. Statistically significant results were seen for both smokers and controls.
... [45] Also reported a high ratio of 1.5 MN in women hairdressers compared to men. In addition, some studies have reported that males are generally more sensitive to MN induction than females [46,47]. However, other studies have indicated no gender-related differences in MN induction, which supports our present findings [48][49][50]. ...
Article
Full-text available
The genotoxic effects, using the micronucleus (MN) test of buccal cells was evaluated in waste pickers working on two major dumpsites (Fegge and Obosi dumpsites) in Onitsha municipal. Sixty waste pickers (30 from each dumpsite) and 30 control individuals of either sex, in the age range of 18 to 54 years participated in the study after giving informed consent. Buccal cells were collected from the buccal mucosa of each participant using sterile wooden spatula. Frequencies of MN and nuclear abnormalities (NA) in 2000 cell were scored for each individual. Significant (P< 0.05) increase in the frequencies of MN and NA were observed in buccal epithelial cells of waste pickers from the two studied dumpsites compared with the control. Significant correlation between sex, age, working hours and years was established with the formation of MN and NA in waste pickers. This study revealed that waste pickers might possibly be at risk of cytogenetic damage from exposure to mixture of pollutants in the dumpsites.
... have reported that there has been a detrimental genotoxic effect of tobacco and alcohol on oral mucosa. They have found that chewing and smoking of tobacco as well as drinking of alcohol enhance the rate of formation of micronuclei in MNC along with other cytological atypias followed by OSCC [54]. The combined effects of tobacco abuse and alcohol consumption are found to be multiplicative. ...
Article
Full-text available
Objective ― The objective of the present study is record the nuclear pleomorphism in various stages of oral carcinogenesis and to analyse their utility in cytopathological grading for early detection of human oral cancer Material and Methods ― In this hospital based case-control study, oral site, age-group and sex-matched 272 subjects (136 cases and 136 normal healthy individuals) were included. Scraped exfoliated cytosmears were collected from the affected oral site of the subjects and smearing was done in the pre-cleaned-coded glass-slides. Two such slides were prepared from each subject. The cytosmears were immediately fixed in aceto-alcohol (1 part of glacial acetic acid: 3 part of absolute ethyl alcohol) fixative. One set of the slide was stained with Papanicolaou’s stain and the other set was counter-stained with Giemsa’s Solution for cytopathological analysis. Test of proportion (z-test) was followed and the critical ratio (z-value) was calculated for the test of significance. Results ― Nuclear pleomorphism in the form of round, oval, spindle, elongated fiber as well as irregular shapes were mostly observed in oral squamous cells during different stages of carcinogenesis. Appearance of such nuclear pleomorphism in human oral neoplasm may be considered as a sign of cellular alternation in general and index of oral carcinogenesis in particular. In the present study, the frank malignant cases mimic to be either premalignant lesions or benign/carcinoma in situ were detected on the basis of nuclear pleomorphism-based cytopathological grading and so an increasing trend was observed from precancerous lesions to malignant cases due to shifting of numbers. Diagnostic tests also indicated that the Sensitivity was calculated to be 83.5%, Specificity was 100%, positive predictive value (PPV) was 100%, negative predictive value (NPV) was 30% and the accuracy was found to be 84.6%. Therefore, the nuclear pleomorphism-based cytopathological grading system makes itself an ideal screening test for early detection of human oral cancer. Conclusion ― Pattern of nuclear pleomorphism corresponding to various cytological atypias is a common feature observed during different stages of oral carcinogenesis and thus, it has a practical implication in grading and early detection of oral cancer.
... MN in exfoliated oral epithelial cells exemplifies a preferred target site for early genotoxic events induced by carcinogenic agents. [1][2][3][4][5][6][7][8][9] Applying this thought, the micronucleus test was applied to oral exfoliated cells taken from the lesional site. ...
Article
Full-text available
Background: Micronuclei (MN) in oral exfoliative cells have been shown to indicate a disparaging change in genetic information of the cell. Recent studies showed correlation between the frequency of MN and severity of this damage. Grading of lesions can be used to determine the austerity of this damage. Aims: The aim of this study is to compare the MN frequency in oral exfoliated cells of normal and oral squamous cell carcinoma (OSCC) individuals and to cytologically grade the frequency of MN in cytological smears and to correlate it with histological grading. The objective is to ascertain whether MN frequency in oral exfoliated cells can be a parameter for grading of OSCC. Settings and Design: The study group comprises of 40 subjects (20 controls and 20 OSCC patients) in the age group of 45-85 years. Materials and Methods: The cytosmear was obtained from each group and stained with Papanicolaou (PAP) stain. Twenty cells from each slide were counted for MN and cytological grade of OSCC was assigned based on the average frequency of MN. Cytological grade was correlated with histological grading and the data were recorded. Student′s t-test and Spearman′s correlation were used for the analysis of the data. Results: Average frequency of MN was 2.5 times higher in OSCC patients when compared to that in controls and the difference was found to be highly significant. Sixty percent correlation was found between cytological grade and histological grade of OSCC and the difference between them was not significant. Conclusions: Cytological grading can be used in grading OSCC, and MN insinuates genotoxic damage occurring in the epithelial cells.
... Compared with persons who neither drink nor smoke, the risk of developing OSCC is increased 80 fold in persons with the highest level of tobacco smoking and alcohol drinking [22]. Mohanta et al. have earlier reported that the combined effect of tobacco and alcohol was found to be more genotoxic than the single use on the buccal mucosal cells [23]. In the present study, all cases were mostly bidi smokers. ...
Article
Full-text available
Background: Palatal neoplasm cases in human are very rare. More than 90% neoplasms of the palate is squamous cell type. Not only cytological pleomorphism but also nuclear anomalies are reported to be observed in oral squamous cell carcinoma (OSCC). But, site specific cytological pleomorphisms are not reported so far. Therefore, an attempt has undertaken to investigate the cytopathology of human palatal neoplasms, pattern of cervical lymph node (CLN) metastasis and to analyse the probable etiological risk factors associated with it in the present study. Methodology: In a hospital-based study, out of 136 oral cases, 9 palatal cases (6 male and 3 female) registered during May 2007 to May 2009 were included in this study. Detail case-history including the nature and types of addiction of each individual was recorded prior to the collection of samples. Two scraped exfoliated cytosmears were collected from the affected site on the pre cleaned-coded glass-slides. Collected cytosmears were immediately fixed in 1:3 aceto-alcohol (1 part of glacial acetic acid and 3 parts of ethyl alcohol). One set of smears was stained with Papanicolaou’s stain and the other was counter-stained with Giemsa’s stain for cytopathological analysis. American Joint Committee for Cancer Staging and End-Results Reporting (AJC) formulated TNM (Tumor-Node-Metastasis) System for staging of OSCC was followed. Result: Cytopathologically, a number of pleomorphic cytological atypias, such as, keratinized spindle cell (KSC), keratinized tadpole cell (KTC), keratinized strap (Antischkow) cell (KSC-A), large and small keratinized fiber cells (KFC), large and small keratinized round cells (KRC), micronucleated cell (MNC), plump keratinized squamous cell (PKSC) and non-keratinized malignant squamous cell (NMSC) were observed in such palatal neoplasms. Except NMSCs, all other cells were keratinized. Out of these, PKSC and MNC were well differentiated; KSC, KTC, KFC, KRC and KSCA were moderately differentiated and NMSC was poorly differentiated. Interestingly, in addition to the micronucleated cell (MNC), KSC-A was found to be a modal cytological atypia irrespective of age, site, sex and degree of pathogenicity which may be attributed to the addiction of tobacco in general and smoking in particular. Conclusion: Chewing and smoking of various form of tobacco and drinking of alcohol contribute a lot to the genesis of cytological pleomorphism in human palatal neoplasm. Typically atypical cells like KSC, KTC, KSC-A, KFC, KRC, PKSC, MNC and NMSCs although found less in number, modal occurrence of KSC-A along with the MNC in all the palatal neoplasm may be directly correlated with any form of tobacco smoking.
... Tobacco and alcohol contain many carcinogenic substances, mostly DNA-toxic carcinogens. It is well known that these carcinogenic substances cause genetic mutations and chromosomal abnormalities followed by micronuclei formation [37,38]. ...
Article
Full-text available
Objectives: During the present investigation, a unique type of pleomorphic cytological atypia- named as nonkeratinized malignant squamous cell (NMSC) was frequently observed in the exfoliated cytosmears of the oral cancer patients. Details of these peculiar atypical, pleomorphic cells have not been reported earlier. Therefore, an attempt has been undertaken to find out the practical utility of NMSCs during difficult diagnoses and in early detection of oral squamous cell carcinoma (OSCC) cases through cytomorphometric analysis. Materials and Methods: In a hospital-based case-control study exfoliated scrape smears were collected from the clinically diagnosed 136 patients suffering from precancerous lesions and cancerous cases and a parallel set of 136 samples were also collected from the non-addicted and non-cancerous healthy individuals considered as control group. Wet fixed smears were stained by adopting Papanicolaou’s staining protocol and counter-stained with Giemsa’s solution. Out of one thousand screened cells, frequently observed NMSCs were scored. Cytomorphometry was done by using computer-assisted Cat Cam 1.30 (1.3 Mega Pixel) Microscope Camera® fitted with hund®-H500 research binocular microscope. The findings were statistically analyzed and interpreted by using software package PAleontological Statistics (PAST)® Version 2.17 with respect to age groups, degree of pathogenicity, oral sites and sexes. Results: Cytomorphometrically, the cellular parameters (mean length, breadth and area) of the NMSC were found to be in decreased state and nuclear parameters are in increased state. The quantitative parameters of the NMSCs were significantly (p ≤ 0.01) decreased with increasing age groups. Cytomorphometrically, the nuclearcytoplasmic (N/C) ratio of the NMSC was found to be 1:1 in both sexes. Conclusion: Extreme reduction of cellular diameter and increased nuclear diameter in each NMSC, lead to cellular non-keratinization, hyperchromasia and increased N/C ratios in both sexes indicate the state of malignancy. Thus, the present finding has a practical utility in early detection and diagnosis of the OSCC patients.
... In their study, they have also reported that appearance of higher percentage of MNCs in non-addicted oral cancer patients than the single addicted (chewers, smokers and alcoholics) groups, has proved the MNC to be an onco-indicator and MNT to be the simplest tool for the test of genotoxicity as well as for the early detection of cancer of the oral cavity. [23] Considering the frequency of MNCs in oral mucosa of normal, precancerous and cancerous groups and their appearance for many years, these seem to represent an early detectable marker of epithelial carcinogenic progression and micronucleus assay in human buccal cells is considered as a tool for biomonitoring DNA damage. [7,24] Jadhav et al. have reported that micronucleus could be a candidate to serve as a biomarker for the prediction of the grade of OSCC. ...
Article
Full-text available
Background: Oral cancer ranks in the top three of all cancers in India, which accounts for over 30% of all cancers reported in the country. The micronucleus test (MNT) is one of the most widely applied short term tests used in genetic toxicology to evaluate the mutagenicity and carcinogenicity. Aims: The present study aims at an in vivo cytogenetic analysis of human oral squamous cell carcinoma and to assess the applicability of MNT in diagnosing early detection of oral carcinoma. Materials and methods: Exfoliated scrape smears were collected from the clinically diagnosed 136 patients suffering from oral precancerous and cancerous lesions. The wet fixed smears were stained by adopting Papanicolaou's staining protocol and counter-stained with Giemsa's solution. Results: The frequency of micronucleated cells has been observed to be in increasing order with the increase of the age-groups and from control to precancerous to cancerous cases significantly in both sexes. Conclusion: Micronucleus formation in the oral mucosa could be a biomarker of genetic damage and also a potential onco-indicator in the long run of oral carcinogenesis. Therefore, MNT can be applied for the early detection of oral carcinoma in the human being.
Article
We investigated the impact of cigarette smoking, daily exposure to tar and nicotine, and the duration of smoking on genetic instability (chromosomal damage—micronuclei, MN, nuclear buds—gene amplification) as well as on disturbances in mitosis (resulting in binucleated cells). Furthermore, we analyzed markers of cytotoxic effects (such as the formation of condensed chromatin, pyknotic, karyolytic, and karyorrhectic cells) and the mitotic activity of the oral mucosa. These parameters were monitored in groups of old (postmenopausal) and young (premenopausal) smoking and nonsmoking women (n = 25/group). We found no differences in the MN frequencies in the non-smoking groups and only a moderate (not significant) increase of MN in both groups of smokers. However, we observed a clear increase in markers of genomic instability in both smoking groups. Furthermore, the mitotic activity of cells in the mucosa and of anomalies caused by acute cytotoxicity was higher in both smoking groups. Nicotine uptake was associated with pronounced acute toxic effects and increased cell division rate. Chromosomal damage (MN) was higher in individuals who consumed high amounts of tar (this effect was not significant) and caused moderate acute toxicity. Our findings indicate (i) that age and hormonal status have no strong impact on the genotoxic and cytotoxic effects in smoking women, (ii) consumption of up to 30 cigarettes/day does not cause chromosomal damage in buccal cells, however, positive results were found in earlier studies in heavy smokers, (iii) smoking increased markers which reflect genetic instability and the division rate of oral mucosa cells. These effects may play a role in the neoplastic transformation of cells in the upper respiratory tract in smokers. The duration of smoking was associated with a slight (not significant) increase in the mitotic activity and of chromosomal damage and with moderate acute cytotoxicity.
Article
Full-text available
Background: Tobacco use continues to be prevalent in our society. It contains many substances which are genotoxic in nature. The genotoxicity of these substances can be studied in human peripheral blood lymphocytes by estimating the average number of micronuclei (MN) by cytokinesis block micronuclei assay (CBMN assay).
Chapter
Micronuclei originate from chromatin which for different reasons has been lagging in anaphase (Fig. la-d). In the course of telophase this material is included into one or the other daughter cell where it either can fuse with the main nucleus or form one or several secondary nuclei. These are, as a rule, considerably smaller than the principal nucleus and are therefore called micronuclei. Lagging has two main causes: chromosome breakage and malfunction of the spindle apparatus. In the first case the lagging elements are acentric chromosome fragments and di- or multicentrics connected by bridges, and in the second case they consist of entire chromosomes.
Chapter
The micronucleus assay was developed to detect in vivo chromosomal breakage more easily than traditional cytogenetic techniques (Heddle, 1973; Schmid, 1973, 1975, 1976; Matter and Schmid, 1971). It was not designed to be a short-term test for carcinogenicity and as such has shown only moderate success in this role, which has sometimes been thrust upon it. As a method for detecting chromosomal breakage, however, it has been quite successful and has largely replaced the traditional scoring of metaphases in bone marrow cells. We have tested more than 100 agents in our laboratory by one or more variations of this assay (Heddle and Bruce, 1977a, 1977b; unpublished data): approximately an equivalent number, including some of the same compounds, have been tested in other laboratories (see, for example: Matter and Grauwiler, 1975; Jenssen and Ramel, 1978; Trzos et al., 1978; Maier and Schmid, 1976; Miller, 1973).
Article
The micronucleus test was applied to buccal mucosa cells of 2 population groups at high risk for oral cancer: Khasis of the northeastern hill region of India, who eat raw betel nuts together with betel leaves and lime, and residents of the state of Orissa (India), who chew betel quids consisting mainly of perfumed tobacco, dried betel nut, betel leaf, lime and several spices. Micronuclei were scored on Feulgen/fast green-stained smear preparations of exfoliated cells obtained by scraping the surface of the buccal mucosa. All 17 raw betel nut eaters and all 20 chewers of betel quids had significantly elevated frequencies of micronucleated mucosa cells over nonchewing controls of comparable ethnic background and dietary habits. The frequencies of micronucleated exfoliated cells were higher at the site within the oral cavity where the quid was kept compared to those at the opposite buccal wall. The micronuclei frequency was lower among individuals chewing a raw betel nut, betel leaf and lime mixture compared to those using tobacco,-betel nut-, lime- and betel leaf-containing quids. Micronuclei frequencies in exfoliated human cells seem to represent a useful 'internal dosimeter' for estimating exposure to genotoxic, and by implication, carcinogenic agents in the tissue from which cancers will develop.
Article
Oral squamous cell carcinoma (OSCC), the most common head and neck malignancy, represents a serious public health problem. Exposure to cigarette smoke (CS)/tobacco is considered responsible for up to 90% of cases of this cancer worldwide. Free radicals, which often originate in CS and reactive nitrogen species, are frequently considered to be the reagents capable of triggering the process leading to malignant transformation. Initially dysplastic lesions of the mucosa are transformed into in situ carcinoma lesions, eventually resulting in a full-blown infiltrating and metastasizing OSCC. A synergistic, deleterious interaction between CS and saliva has been reported, which may result in the rapid destruction of biological macromolecules such as enzymes and proteins, giving it a possible pivotal role in the pathogenesis of OSCC. This lethal synergistic effect of CS and saliva is probably based on the reaction between redox-active metals in saliva and low reactive free radicals in CS. This is a novel concept recognizing that when exposed to CS, salivary behavior is reversed and saliva loses its antioxidant capacity, becoming a potent pro-oxidant milieu.
  • A Halder
  • T Chakraborty
  • K Mandal
  • P K Guru
  • S Das
  • R Roychoudhury
  • A K Ghosh
  • M De
Halder, A., Chakraborty, T., Mandal, K., Guru, P.K., Das, S., Roychoudhury, R., Ghosh, A.K., De, M., Int. J. Hum. Genet., 2004, 4(4), 257-260.
  • A Bhattacharjee
  • A Chakroborty
  • P Purkayastha
Bhattacharjee, A., Chakroborty, A. and Purkayastha, P., Ind. J. Otolaryngol. Head and Neck Surg., 2006, 58(1), 15-19.
  • W Schmid
Schmid, W., Mutat. Res.,1975, 312, 9-15.
Micronucleus test: an in vivo bone marrow method
  • W Schmid
Schmid, W. Micronucleus test: an in vivo bone marrow method. In Hsu TC (Ed) Cytogenetic Assays for Environmental Mutagens, (Oxford and IBH Publishing Co., New Delhi), 1982, 221-229.