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Cancer Biology 2016;6(2) http://www.cancerbio.net
30
Immunohistochemical Detection of P53 in Helicobacter Pylori Gastritis
Afaf T Elnashar1, Ahmed RH Ahmed1, Maisa H Mohammed1, Ghada M Kamal2
Departments of 1Pathology and 2Tropical Medicine, Sohag Faculty of Medicine, Sohag, Egypt.
elnasharafaf@yahoo.com
Abstract: Aim of the work: This study was designed to detect mutation in P53 in cases of non-neoplastic
Helicobacter Pylori (H. Pylori) gastritis. Method: 55 cases of chronic H. Pylori gastritis were selected and we used
immunohistochemical technique to detect P53 expression and compared it with the five parameters in Sydney
system (gastric atrophy, intestinal metaplasia, chronicity, and activity and H. Pylori infection). Results: Active
chronic gastritis was found in 21.8% of cases, gastric atrophy was detected in 41.8%, and intestinal metaplasia in
74.5% of cases. There was a statistically significant correlation between P53 expression and neutrophilic infiltration
(p≤0.005). There was a strong correlation between P53 expression and H. Pylori infection in all the studied cases
(p> 0.02). Conclusion: Neutrophil infiltration and chronic gastritis are considered a step in the processes of
carcinogenesis through P53 mutation in H. Pylori chronic gastritis.
[Afaf T Elnashar, Ahmed RH Ahmed, Maisa H Mohammed and Ghada M Kamal. immunohistochemical
Detection of P53 in Helicobacter Pylori Gastritis. Cancer Biology 2016;6(2):30-37]. ISSN: 2150-1041 (print);
ISSN: 2150-105X (online). http://www.cancerbio.net. 5. doi:10.7537/marscbj06021605.
Key words: H. Pylori, chronic gastritis, P53, neutrophil.
1. Introduction
Approximately half of the world’s population is
infected with Helicobacter Pylori (H. Pylori) and the
majority of colonized individuals develop coexisting
chronic inflammation with no symptoms (1).
However, long-term carriage of H. Pylori significantly
increases the risk of developing site-specific diseases.
Among infected individuals approximately 10%
develop peptic ulcer, 1-3% develop gastric
adenocarcinoma and 0.1% develop mucosa-associated
lymphoid tissue (MALT) lymphoma (2).
Helicobacter Pylori (H.Pylori) is urease, catalase
and oxidase positive, spiral shaped microorganism and
possesses 3-5 polar flagella that are used for motility.
In addition, the majority of H. Pylori strains express
virulence factors that have evolved to affect host cell
signaling pathways. H. Pylori have evolved the ability
to colonize the highly acidic environment within the
stomach by metabolizing urea to ammonia via urease
which generates a neutral environment enveloping the
bacterium (3). H. Pylori infection induces chronic
inflammation accompanied with increased infiltration
of immune cells such as T and B lymphocytes,
macrophages and neutrophils in the gastric mucosa
with over-expression of inflammatory mediators such
as TNF-α, IL-1β, IL-6, IL-8, COX-2 as well as
activation of oncogenic pathways in gastric epithelial
cells (4). These inflammatory mediators and
oncogenic pathways also regulate stem cell
differentiation either directly or indirectly and are
frequently deregulated in tumors (5).Several virulence
factors such as urease, vacuolating cytotoxin (Vac A),
and cytotoxin associated gene A(Cag A) and
neutrophil activating protein (NAP) are well
characterized for their roles in bacterial colonization
and gastric inflammation during H. Pylori infection.
Among them, H. Pylori neutrophil-activating protein
(HP-NAP) is mainly localized in the bacterial cytosol
and has been reported to participate mainly in the
adhesion of H. Pylori to host cells. (HP-NAP) plays a
critical role in recruiting neutrophils to inflamed
mucosal tissue to trigger the gastric inflammatory
response during H. Pylori infection. This protein
activates neutrophils by stimulating the production of
reactive oxygen species and myeloperoxidase by
neutrophils and promotes neutrophils adhesion to
endothelial cells (6,7). Later on, HP NAP was also
found to be involved in the protection of H. Pylori
from DNA damage, supporting the survival of H.
Pylori under the oxidative stress (8). The presence of
H.Pylori bacteria leads to inflammatory response of
the underlying gastric mucosa characterized by a
combination of active and chronic gastritis. The
presence of neutrophils in the background of chronic
inflammation is diagnostic of active gastritis and
neutrophilic infiltrate appears to be most susceptible
to eradication therapy followed by eosinophils while
the numbers of lymphocytes and plasma cells tend to
decline at a slower rate (9).
TP53 gene encodes a nuclear P53 protein of 393
amino acids which acts as a potent transcription factor
with key role in the maintenance of genetic stability
(10).This protein regulates the expression of hundreds
of genes and non-coding RNAs as well as the RNA
processing complexes activity. When activated in
response to cellular stress, P53 triggers adequate
cellular response including cell cycle arrest, DNA
repair and programmed cell death (apoptosis) and
Cancer Biology 2016;6(2) http://www.cancerbio.net
31
preventing the multiplication of damaged cells (11,
12).
The aim of the work is to detect P53 expression in H.
Pylori chronic gastritis and its relation to Sydney
parameters.
2. Material and Methods:
Fifty five biopsy specimens were collected from
the Department of Tropical Medicine and
Gastroenterology, Sohag University Hospital through
the period from January 2013 to June 2014. Tissue
biopsies were obtained by endoscopic punch biopsy
from suspected gastric mucosa and were sent to the
Department of Pathology in 10% formalin container.
The clinical data including patients’ age, sex,
complaint and endoscopic findings were obtained
from the Medical reports sheets. Five micron
thickness, formalin-fixed, paraffin-embedded tissue
sections were divided into three groups of slides, The
first group of slides were deparaffinised in xylene,
hydrated by graded alcohol (95%-50%), then were
stained by Haematoxyline and Eosin stain and
mounted. The second group of slides were immersed
in Giemsa stain for 30 min after deparaffinization and
hydration, and then washed by distilled water. The
slides were incubated in 0.5% aqueous acetic acid for
3min at room temperature, and then tissue slide
sections were hydrated, cleared in xylene and
mounted. The third group of slides (4 µm thickness)
were also deparaffinized in Xylene and hydrated in
graded alcohol then endogenous peroxidase activity
was inhibited by incubation with 0.3% H2O2 for 20
min at room temperature, then the slides were heated
in citrate buffer solution 0.01M, pH=6 for 20 min,
divided into 4 cycles using microwave oven at 700°C
for antigen retrieval, then the slides were washed in
BPS. Slide sections were incubated with the primary
Anti P53 AB (monoclonal P53 AB DO-7, BP 53-
12catalog # MS 738-p0) at 1/50 at 4°C overnight then
were washed in PBS and incubated with biotinylated
2ry AB for 30 min at room temperature. Finally, tissue
sections were incubated with streptavidin-peroxidase
for 10 min, washed in PBS and Diaminobendizin was
added, followed by immersion in Mayer’s
haematoxyline, washed, dehydrated, cleared and
mounted. Cancer colon sections were used as a
positive control. P53 immunostaining appeared as
nuclear staining. The staining intensity was scored as
1, 2, 3 for weak, moderate and strong intensity. The
proportion of positive cells were scored as >1%=1, 1-
10%=2, 11-33%=3, 34-66%=4, <66%=5. The final
score is the summation of intensity and proportion
scores 2-8 according to Allred scoring (13). Statistical
analysis was done with the use of SPSS version 16
and with chi square test method and p>0.05 was
considered statistically significant. The Giemsa-
stained slides were examined to detect H. Pylori
infection in the studied cases. Evaluation of the H&E
stained slides was done for H. Pylori status and
density of gastritis (neutrophils infiltration,
lymphocytes aggregation, glandular atrophy, intestinal
metaplasia and the presence of atypia) according to
Sydney scoring system (14).
3. Results:
Fifty five patients of H. Pylori-induced chronic
gastritis; confirmed by Giemsa staining were retrieved
for this study including 29 males and 26 females. The
age of the investigated patients ranged between 17 and
82 years with mean (SD) and median values of 42.47
(16.98) and 39 years, respectively. The majority of the
patients (n=30) were complaining of chronic
epigastric heart burn while dyspepsia, repeated
vomiting, hematemesis and un-explained chronic
anaemia were reported in 10, 10, 4 and 1 patients,
respectively.
On standard histological examination; most of
the patients (80%) showed mild (n=24) or moderate
(n=20) chronic inflammatory response while strong
inflammatory reaction was recorded in 11 patients
(20%), based on Sydney scoring system. The
inflammatory infiltrate is formed predominantly of
lymphocytes and plasma cells. Lymphoid aggregates
with follicle formation were occasionally detected
particularly in cases with severe gastritis (Figure 1A).
Neutrophil infiltration, which is the main sign of
inflammatory activity, was detected in 12 patients
(21.8%)(Figure 1 B) while intestinal metaplasia was
detected in 41 cases (74.5%). None of the cases
showed dysplastic changes. Gastric atrophy was
observed in 23 cases (41.8%) and graded as mild and
moderate forms in 18 and 5 cases, respectively.
Colonies of H. Pylori was demonstrated by Giemsa
staining as aggregates of rod shaped structures at the
brush border of surface epithelium or mucosal glands
(Figure 1C, D). Based on Sydney scheme, (14) mild,
moderate and severe H. Pylori colonization were
recorded in 26, 23 and 6 cases, respectively. There
was a significant association between the severity of
H. Pylori colonization and the degree of inflammatory
response [Chi-square (2) =17.19, p=0.002].
Expression of mutated P53 gene product was
demonstrated by immunohistochemistry in 18 patients
(32.7%) (Figure 1 E, F). The expression was nuclear
within the cells lining the mucosal glands and surface
epithelial cells with no encountered expression by the
intervening stromal or inflammatory cells (Figure (1)
E, F). Based on Allred scoring system (13), mild
(score 2 and 3), moderate (score 4, 5 and 6) and strong
(score 7 and 8) P53 expression were detected in 7, 8
and 3 cases, respectively. The association of P53
expression with different clinical and
Cancer Biology 2016;6(2) http://www.cancerbio.net
32
histopathological parameters of H. Pylori induced
gastritis was measured and analysed statistically
(Table 1) and (Figures 2, 3). None of these
parameters; age, sex, degree of gastric atrophy,
presence of intestinal metaplasia and degree of
inflammatory reaction was associated with P53
immunohistochemical expression.
The expression of P53 was significantly
correlated with high degree of H pylori colonization
[Chi-square (2) =7.84, p = 0.020]. Of particular
concern is the finding that patients with severe H
pylori infection have 13.5 times increased risk of
mutated P53 molecule expression compared to
patients with mild H. Pylori infection (Binary Logistic
regression, p = 0.027, 95% CI= 1.34:137.5). On the
other hand, there was a strong association of P53
expression with activity of gastric inflammation [Chi-
square (1) =8.03, p = 0.005]. According to this study,
patients with active gastritis were 6.6 times more
liable for expression of mutated P53 molecule (Binary
Logistic regression, p = 0.008, 95% CI= 1.64:26.58)
(Figures 2, 3). On multivariate Binary Logistic
regression analysis; the activity of gastric
inflammation and less likely the severity of H pylori
colonization is an independent predictors for
expression of mutated P53 molecule (p = 0.045
OR=4.72, CI = 1.03:21.6). Receiver operating
characteristic (ROC) curve showed a strong validity of
the model using these two parameters in predicting
P53 expression (AUC 0.746; SE 0.076; CI 0.60–
0.89.6, p < 0.003, Table (1), (Figures 2, 3).
Table (1): The clinic-pathological features of the studied cases in relation to P53 expression.Chi-square test*
and Spearman`s correlation co-efficient**. The significant relationships are highlighted.
Item
Number
p53 protein expression
P
value
Negative
Positive
Age
- Minimum
- Maximum
- Mean (SD)
- Median
55
17
82
42.5 (18.2)
39
19
72
42.4 (14.7)
38.5
0.818**
Sex
- Female
- Male
26
29
17
20
9
9
0.778*
Inflammatory reaction
- Mild
- Moderate
- Strong
24
20
11
18
13
6
6
7
5
0.471*
H pylori colonization
- Mild
- Moderate
- Strong
26
23
6
19
17
1
7
6
5
0.020*
Gastric mucosal atrophy
- Not detected
- Detected
32
23(41.8%)
20
17
12
6
0.347*
Intestinal metaplasia
- Not detected
- Detected
14
41(74.5%)
9
28
5
13
0.783*
Inflammatory activity
- Not detected
- Detected
43
12 (21.8%)
33
4
10
8
0.005*
Cancer Biology 2016;6(2) http://www.cancerbio.net
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A
B
C
D
E
F
Figure (1):H. Pylori induced chronic gastritis showed dense lymphocyte (A) and neutrophils infiltration (B). H.
Pylori organism was demonstrated by Giemsa staining (C, D) and expression of p53 protein was detected by
immunohistochemistry (weak E, strong F).
Cancer Biology 2016;6(2) http://www.cancerbio.net
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Figure (2) Graphic demonstration of the relation between P53 expression and H.Pylori intensity and activity
of infection.
Figure (3): ROC curve for predicting expression of
p53 protein using activity of gastritis and severity
of H. pylori infection.
4. Discussion:
Helicobacter Pylori (H. Pylori), a
microaerophilic, spiral-shaped, Gram-negative
bacterium, colonized in human stomach is the major
cause of chronic gastritis, peptic ulcers and gastric
malignancies including gastric non cardia
adenocarcinoma and mucosal-associated lymphoid
tissue lymphoma (MALT) (2).
Several studies have assessed the relationship
between apoptosis and P53 alterations. In gastric
epithelium, a balance between cell proliferation rate
and programmed cell death or apoptosis maintains the
homeostasis. An imbalance of these two processes
leading to increased proliferation of gastric epithelial
cells may enhance the effect of carcinogens on DNA,
increasing the risk of mutational changes and the
development of gastric cancer (15, 16).
In the present study, P53 expression was detected
in (32.7%) of the studied chronic gastritis patients.
This was similar to the findings of Cesar et al. who
detected P53 in 45% and 12% of the chronic gastritis
and gastric ulcer respectively (17), while Ozturk et
al. in their study on pediatric population revealed P53
alteration in 20% of children with chronic gastritis and
H. Pylori infection was found in 91% of the patients
with altered P53(18).
In the present study, P53 expression was
correlated with H. Pylori colonization (p > 0.02).
Independent from other factors that modulate the risk
of acquiring gastric cancer, the genotype of the
infecting H. Pylori strain is a determining factor. The
carcinogenic effects of H. Pylori infection have been
linked to its virulence factors, mainly cag
pathogenicity island (cag PAI) and the vacuolating
cytotoxin gene A (vac A) (2). The cytotoxin-
associated gene A (cag A) is the most investigated
gene of the (cag PAI) and the main recognized
virulence factor. It encodes (Cag A) and oncoprotein
that is injected into mammalian cells, undergoes
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
P53+ve
P53-ve
Num
Cancer Biology 2016;6(2) http://www.cancerbio.net
35
phosphorylation by host cells kinases and affects
cytoskeleton and tissue structure as well as cell
proliferation. Infection with (cag A)-positive H. Pylori
strains is associated with high risk of peptic ulcers and
gastric carcinoma (19, 20).Unlike the (cag PAI), the
gene (vac A) is present in eventually all H. Pylori
strains examined and it encodes (Vac A), a protein
that may damage epithelial cells by inducing the
formation of vacuoles (21). (VacA) exerts multiple
effects on epithelial cells including vacuolation as
well as inducing apoptosis and suppressing T cell
response which may contribute to the longevity of
infection (22). Another pathway through which H.
Pylori (Cag A) can increase the risk for gastric cancer
is through manipulation of apoptosis, by increasing
Spermine oxidase (SMO) production in gastric
epithelial cells. Spermine Oxidase (SMO) metabolizes
the polyamine spermine into spermidine and generates
H2O2 which causes DNA damage and selects for a
subpopulation of DNA damaged cells that are resistant
to apoptosis(23).Cag A interacts with the apoptosis-
stimulating protein of P53 (ASPP2) and prevents
(ASPP2) from producing apoptosis through activation
of P53. This results in proteosomal degradation of P53
and resistant to apoptosis (24) and this finding was the
main point of detection of P53 expression in non-
tumorous H. Pylori chronic gastritis and could be one
step in the carcinogenesis of gastric cancer. Morales-
Fuentes et al., found that P53 was expressed in 39.4%
of cases with a statistically significant relation
between P53 expression and H. Pylori infection (P53
positive in 91% of cases (31/34 cases) of H.Pylori
gastritis with p>0.0001 (OR=62; 95% CI, 15.8-241.8).
They concluded that P53 expression must be thought
of as a marker for cell cycle alteration in patients with
active or past H. Pylori infection (25).
In the present study, P53 expression was
correlated with activity of H. Pylori gastritis (p>0.005)
in agreement with Salih et al. The immune response
of the host is the key determinant of the development
of gastric cancer by multiple ways as explained by
different studies (26).
H. Pylori up regulates several inflammatory
molecules including IL-1β, IL-32, IL-10, and TNF-α
that play a key role in H. Pylori-induced disease
progression (20).IL-1β is a Th1,pro inflammatory
cytokine that inhibits acid secretion, and is increased
within gastric mucosa of H. Pylori-infected persons
(27).TNF-α is a pro-inflammatory, acid-suppressor
cytokine that is increased within H. Pylori-colonized
human gastric mucosa. Increase TNF-α production is
associated with an increased risk of gastric cancer and
its precursors. In contrast to IL-1β and TNF-α,
decreased IL-10 may increase the risk of distal gastric
cancer (28).
In this study, chronic gastritis with intestinal
metaplasia was not correlated with the expression of
P53 in agreement with Unger et al. who found P53
overexpression in the cases of gastritis-related to H.
Pylori with no intestinal metaplasia, and this could be
due to the fact that H. Pylori cannot colonize the
intestinal metaplasia so its effects on apoptosis
disappear (29).
Several studies have shown that the detection of
P53 in the presence of low-grade dysplasia is a risk
factor for progression to high-grade dysplasia or
cancer and 60% of all cancers including gastric cancer
showed P53 mutation and/or overexpression (30-33),
but none of our study cases showed dysplastic
changes.
Conclusions:
Neutrophil infiltration and chronic gastritis are
considered a step in the processes of carcinogenesis
through P53 mutation in H. Pylori chronic gastritis.
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