Dujo Kovacević

Sisters of Charity Hospital Zagreb, Zagreb - Centar, Grad Zagreb, Croatia

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Publications (13)63.38 Total impact

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    ABSTRACT: Background: Detection of circulating cancer cells by reverse transcription polymerase chain reaction (RT-PCR) has been studied as a prognostic marker in patients with colorectal cancer (CRC) but so far with conflicting results regarding specificity and prognostic value. In this study cytokeratin-20 (CK20) was evaluated by real-time RT-PCR as a marker for circulating CRC cell detection and the influence of surgical tumor resection on the presence of circulating CRC cells was analyzed. Methods: RNA was isolated from the mononuclear cell fraction of blood samples taken from 95 CRC patients before and after tumor resection and from 23 healthy volunteers and assayed by real-time RT-PCR for CK20 expression. Results: Among 23 healthy volunteers one was positive for CK20. Among 95 CRC patients, 25 were positive for CK20 before and 23 after surgery. Sixteen patients positive before surgery became negative after surgery, while 14 patients negative before surgery became positive after surgery. An increase in the proportion of CK20-positive samples with increasing stage of disease was observed for preoperative but not postoperative blood samples. Conclusions: Its association with clinical stage indicates that CK20 might have prognostic value as a marker for detection of circulating CRC cells. Surgical tumor resection can both reduce and induce the presence of circulating CRC cells.Obesity is associated with breast cancer in post-menopausal women, and breast density is a marker of breast cancer risk. Leptin is produced by the adipose tissue, acts through receptors that are polymorphic in nature, and is considered a cancer growth factor. The relationship between body mass index, leptin, leptin receptors and breast density is not well studied. A cross-sectional analysis in 392 post-menopausal healthy women was conducted; participants provided permission to obtain copies of their most recent screening mammogram. Non-fasting plasma leptin levels were determined using a commercially available leptin ELISA kit. Analysis of the Q223R genotypes of the LEPR gene were performed by PCR followed by restriction fragment length polymorphism analysis using DNA extracted from buffy coat samples.A statistically significant positive relationship was observed between leptin levels and body mass index (p<0.0001); leptin was significantly positively associated with mammography total breast area and non-dense breast area (p<0.0001), while it was inversely associated with percent breast density (p<0.0001). Leptin levels varied across the LEPR Q223R polymorphism, and were higher in women homozygous for the AA variant. Percent breast density decreased across the LEPR Q223R genotype, with lower percent density in women with the AA genotype. When dense area was considered according to quartiles of leptin and stratified by LEPR Q223R , a significant inverse trend between leptin levels and dense breast area was observed only among women with the G/G genotype (p-trend<0.001). After adjustment for possible confounders, leptin levels were significantly inversely associated with percent breast density (p=0.01). A significant interaction between body mass index and leptin levels on percent breast density was observed (p=0.03).These findings suggest that the association between leptin and breast density may vary by LEPR Q223R genotype, and that body mass index and leptin may act in an interactive way in determining breast density.
    The International journal of biological markers 04/2013; · 1.59 Impact Factor
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    ABSTRACT: Twenty common genetic variants have been associated with risk of developing colorectal cancer (CRC) in genome wide association studies to date. Since large differences between populations exist, generalisability of findings to any specific population needs to be confirmed. THE AIM OF THIS STUDY WAS TO PERFORM AN ASSOCIATION STUDY BETWEEN RISK VARIANTS: rs10795668, rs16892766, rs3802842 and rs4939827 and CRC risk in Croatian population. An association study was performed on 320 colorectal cancer cases and 594 controls recruited in Croatia. We genotyped four variants previously associated with CRC: rs10795668, rs16892766, rs3802842 and rs4939827. SMAD7 variant rs4939827 (18q21.1) was significantly associated with CRC risk in Croatian population. C allele was associated with a decreased risk, odds ratio (OR): 0.70 (95% CI: 0.57-0.85, P=3.5E-04). Compared to TT homozygotes, risk was reduced by 34% in heterozygotes (OR=0.66, 95% CI: 0.47-0.92) and by 52% in CC homozygotes (OR=0.48, 95% CI: 0.33-0.72). Our results show association of rs4939827 with colorectal cancer risk in Croatian population. The higher strength of the association in comparison to other studies suggests population-specific environmental or genetic factors may be modifying the association. More studies are needed to further describe role of rs4939827 in CRC. Likely reason for failure of replication for other 3 loci is inadequate study power.
    PLoS ONE 01/2013; 8(9):e74042. · 3.73 Impact Factor
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    ABSTRACT: We performed a meta-analysis of five genome-wide association studies to identify common variants influencing colorectal cancer (CRC) risk comprising 8,682 cases and 9,649 controls. Replication analysis was performed in case-control sets totaling 21,096 cases and 19,555 controls. We identified three new CRC risk loci at 6p21 (rs1321311, near CDKN1A; P = 1.14 × 10(-10)), 11q13.4 (rs3824999, intronic to POLD3; P = 3.65 × 10(-10)) and Xp22.2 (rs5934683, near SHROOM2; P = 7.30 × 10(-10)) This brings the number of independent loci associated with CRC risk to 20 and provides further insight into the genetic architecture of inherited susceptibility to CRC.
    Nature Genetics 05/2012; 44(7):770-6. · 35.21 Impact Factor
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    ABSTRACT: To estimate the incidence and mortality trends of gastric and colorectal cancers in Croatia between 1988 and 2008. Incidence data for the period 1988-2008 were obtained from the Croatian National Cancer Registry. The number of deaths from gastric and colorectal cancers were obtained from the World Health Organization mortality database. Joinpoint regression analysis was used to describe changes in trends by sex. Gastric cancer incidence rates declined steadily during the study period, with estimated annual percent change (EAPC) of -3.2% for men and -2.8% for women. Mortality rates in men decreased, with EAPC of -5.0% from 1988-1995 and -2.5% from 1995-2008. Mortality rates in women decreased, with EAPC of -3.2% throughout the study period. For colorectal cancer in men, joinpoint analysis revealed increasing trends of both incidence (EAPC 2.9%) and mortality (EAPC 2.1%). In women, the increase in incidence was not significant, but mortality rates in the last 15 years showed a significant increase (EAPC 1.1%). The incidence and mortality trends of gastric cancer in Croatia are similar to other European countries, while the still increasing colorectal cancer mortality calls for more efficient prevention and treatment.
    Croatian Medical Journal 04/2012; 53(2):124-34. · 1.25 Impact Factor
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    ABSTRACT: Gallstone ileus with impaction of gallstone in distal duodenum is an extremely rare complication of cholecystolithiasis. Gallstone ileus in itself accounts for less than 1% of these complications with 800 cases described so far. However, there are less than 15 cases described with the impaction of gallstone in distal duodenum. We report a case of an 84-year-old male patient in whom gallstone impacted in distal duodenum was found by ultrasonography and confirmed by computed tomography. Cholecystitis and a remaining large gallstone in the gallbladder were found intraoperatively, which made us opt for one-step procedure, i.e. lithotomy and fistula repair with cholecystectomy. Due to the rare position of impacted gallstone, we believe that cases like this should be reported in detail in order to generate enough data for establishing optimal treatment options.
    Acta clinica Croatica 09/2010; 49(3):305-8. · 0.28 Impact Factor
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    ABSTRACT: The aim of this study was to analyze microphthalmia-associated transcription factor (MITF) as a marker for the detection of circulating melanoma cells, determine its prognostic value in melanoma patients, and compare it with tyrosinase. Blood samples from 201 melanoma patients in all stages of the disease and 40 healthy volunteers were analyzed. RNA was isolated from mononuclear cell fraction of the blood and assayed by reverse transcription-PCR for the expression of MITF and tyrosinase. All samples from healthy volunteers were negative for both MITF and tyrosinase. Out of 201 blood samples from melanoma patients 32 were positive for MITF, 20 for tyrosinase, and four for both MITF and tyrosinase. Analysis of MITF as an additional marker to tyrosinase allowed for detection of circulating melanoma cells in a larger number of melanoma patients in comparison to tyrosinase analysis alone (48 vs. 20 positive). A positive value of MITF was associated with shorter progression-free (P=0.005) and overall survival (P=0.042). A positive value of tyrosinase was associated with shorter overall survival (P=0.012), whereas there was no significant association between the value of tyrosinase and progression-free survival. The value of MITF was selected with multivariate analysis as the independent prognostic factor for progression-free survival, whereas the only independent prognostic factor for overall survival was the stage of disease. This study has shown that MITF is a specific marker for detection of circulating melanoma cells that has a prognostic value in melanoma patients. Determination of MITF in addition to tyrosinase improved the detection of circulating melanoma cells in melanoma patients.
    Melanoma research 03/2010; 20(4):293-302. · 2.06 Impact Factor
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    ABSTRACT: Soluble c-erbB-2 oncoprotein has been proven as a useful marker in the management of breast cancer patients, but its value in diagnostics and follow-up of colorectal cancer patients remains controversial. The aim of this study was to evaluate the usefulness of serum c-erbB-2 monitoring in diagnostics and prediction of disease outcome in rectal cancer patients. Serum samples from 88 patients with rectal adenocarcinoma before surgery and from 41 healthy controls were tested for the presence of c-erbB-2 oncoprotein by ELISA, and the patients were followed up for at least 5 years after the surgery. Preoperative serum c-erbB-2 levels were significantly higher in stage IV patients than in healthy controls (P<0.001) and did not show correlation with preoperative CEA levels. Elevated preoperative serum c-erbB-2 levels showed relatively high specificity (88%) and low sensitivity (44%) in the diagnosis of rectal cancer. Elevated preoperative oncoprotein levels were predictive neither for overall survival nor for development of local recurrence/distant metastases. Although preoperative serum c-erbB-2 levels were significantly higher in rectal cancer patients than in healthy controls, the soluble c-erbB-2 does not seem to be useful in the diagnosis of rectal cancer due to its low sensitivity. Preoperative serum levels of this oncoprotein were predictive neither for overall survival nor for local recurrence/distant metastases in rectal cancer patients.
    International Journal of Colorectal Disease 07/2007; 22(7):827-31. · 2.24 Impact Factor
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    ABSTRACT: The total number of 542 patients with colorectal cancer surgery have been analyzed in order to estimate the effect of receiving transfusion local recurrences, and the disease free - survival. It should be examined whether there are changes in general immunity indicators which would be connected with perioperative transfusion. A significant connection has been found between local recurrences and blood transfusion (p<0.0001), the most noticeable being in Dukes A (p =0.045), localization on rectum (p=0.036). The receiving of blood transfusion is linked significantly with disease free - survival reduction (p =0.0068; log rank), the most significant being in Dukes A stage (p =0.0123; log rank) and with localization on rectum (p=0.0231). The analysis of general immunity indicators has shown significant immunocompromitation of patients just before the surgery and this could have effect on immunomodulation caused by transfusion and just as on the treatment prognosis of colorectal carcinoma.
    Collegium antropologicum 01/2007; 30(4):885-93. · 0.61 Impact Factor
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    ABSTRACT: Overexpression of p53 protein in malignancies induces an immune response in some cancer patients. We investigated whether production of serum antibodies against p53 (p53-Ab) is associated with pathohistological parameters of colorectal carcinoma and whether p53-Ab can serve as a tumor marker during cancer treatment. Serum samples from 220 colorectal cancer patients during surgery and adjuvant chemotherapy and 42 healthy controls were tested for the presence of p53-Ab by ELISA. Expression of p53 protein in tumors was determined using mouse anti-human p53-Ab. Serum p53-Ab were detected in 18% of patients while all controls were negative. A strong correlation between p53-Ab production and p53 protein expression was observed: 70% of p53-Ab positive cases had tumors positive for p53 vs. 52% of p53-Ab negative cases. There was also a significant predominance of p53-Ab positive cases in Dukes' stages B and C over stage A. Although surgery alone reduced p53-Ab levels, decreases in p53-Ab titer became significant midterm through chemotherapy compared to both pre- and postoperative values and remained decreased until the completion of treatment. The presence of p53-Ab in sera of patients with colorectal cancer indicates tumors in more advanced histopathologic stages (Dukes' B, C). Due to low sensitivity (18%) p53-Ab are not recommendable as a preoperative marker for colorectal cancer. However, due to high specificity (100%), their monitoring after surgery and adjuvant chemotherapy has potential for early diagnosis of tumor relapse in p53-Ab positive cases.
    International Journal of Colorectal Disease 04/2004; 19(2):114-20. · 2.24 Impact Factor
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    ABSTRACT: We investigated the prevalence of DPC4 loss of heterozygosity in sporadic colorectal cancer. Thirty-six cases of human sporadic colon carcinoma and corresponding normal tissue samples were examined to evaluate loss of heterozygosity at the DPC4 tumor suppressor locus using variable nucleotide tandem repeat (VNTR) analysis and three polymorphic markers. From 36 analyzed samples 35 (97%) were heterozygous or informative. Loss of heterozygosity at the DPC4 locus was detected in 18 (51%) of informative tumor DNAs. The DPC4 LOH was more frequent in smaller tumors (<5 cm) than in larger ones. There was no correlation between DPC4 LOH and age or sex of patients. There was a negative correlation between DPC4 LOH and histological grade or Dukes' stage of tumors, but without statistic significance. Observed results are in agreement with the view that malignant progression is consequence of many genetic changes. It can be concluded that inactivation of the DPC4 gene plays a role in a multistep process of outgrowth and progression of colon cancer.
    Journal of Molecular Medicine 05/2001; 79(2-3):128-32. · 4.77 Impact Factor
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    ABSTRACT: Nonsteroidal anti-inflammatory drugs lower the incidence of and mortality from colon cancer. In this paper, we present the effect of indomethacin on growth inhibition and alterations in the expression of several genes involved in cell cycle and apoptosis in CaCo-2 colon adenocarcinoma cells. We used the MTT test to evaluate the effect of indomethacin on the proliferation rate of colon cancer and normal fibroblast cells in vitro. The expression of c-myc oncoprotein and p53 and p27 suppressor proteins was examined using the immunocytochemical method. We have shown that indomethacin reduces the proliferation rate of CaCo-2 colon cancer cells (up to 60% at the concentration of 4 x 10(-4) M), alters their morphology, and induces cell death by apoptosis. The most pronounced inhibitory effect was observed at the concentration of 6 x 10(-4) M where the growth was completely suppressed. However, the growth of normal fibroblasts (Hef 522) was much less inhibited (about 30% of inhibition at the concentration of 6 x 10(-4) M). Indomethacin reduces the proliferation rate and induces apoptosis in CaCo-2 colon cancer cells through enhanced expression of c-myc, p53, and p27 proteins. This is the first report about p27-increased expression in colon carcinoma cells induced by indomethacin treatment. Increased expression of p27 represents a new mechanism of apoptosis in cells treated with NSAIDs (indomethacin). This effect probably contributes to the anti-proliferative effect on colon cancer cells in vitro.
    Journal of Cancer Research and Clinical Oncology 02/2001; 127(3):173-9. · 2.91 Impact Factor
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    ABSTRACT: We examined 36 cases of human sporadic colon carcinoma and corresponding normal tissue samples to evaluate loss of heterozygosity at the APC and DCC tumor suppressor genes loci using restriction fragment length polymorphism polymerase chain reaction and variable nucleotide tandem repeat analysis. Observed informativity was 83% for APC and 75% for DCC. DNA from 6 (20%) of 30 informative tumors exhibited loss of heterozygosity at the APC locus. Loss of heterozygosity at the DCC locus was observed in 7 (26%) of 27 informative tumor DNAs. Our results support the view that malignant progression is a consequence of more than one genetic change and suggest that inactivation of APC and DCC genes plays a role in a multistep process of colon tumor progression.
    Journal of Molecular Medicine 04/1999; 77(3):316-21. · 4.77 Impact Factor
  • J Lukac, Z Kusić, D Kovacević, Z Soldić, B Troskot
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    ABSTRACT: Neutrophil and monocyte phagocytic functions, i.e % of phagocytic cells, ingestion and intracellular microbe killing were determined in 51 patients with colorectal adenocarcinoma, 43 with localized disease and 8 with distant metastases. Phagocytic functions were determined at the time of diagnosis, following surgery are before each of 6 cycles of fluorouracil chemotherapy. Four of six phagocytic parameters determined were decreased at diagnosis while all 6 decreased following surgery. During chemotherapy, neutrophil phagocytic activity recovered to normal value while all other neutrophil and monocyte functions remained decreased. Even so, neutrophil ingestion and monocyte phagocytic and bactericidal activities increased reaching from time to time values significantly higher than that found before the start of chemotherapy. The results showed significant alterations of neutrophil and monocyte phagocytosis in colorectal adenocarcinoma patients at the time of diagnosis, with further decrease following surgery. Fluorouracil chemotherapy did not exert suppressive effects on these functions; on the contrary, it seemed to support, or at least not to prevent, their partial recovery.
    Anticancer research 15(6B):2805-9. · 1.71 Impact Factor