Evaluation of Polymorphisms_rs 762624 and rs3176336 of CDKN1A Gene and Risk of Colorectal Cancer.

Aims: Progressive loss of cell cycle control is an important feature on the colorectal cancer. CDKN1A gene encoded p21 protein that’s one of the cyclin-dependent kinase inhibitors, plays a key role in regulating the cell cycle. The aim of this study was toinvestigate associations of the CDKN1A gene polymorphism rs762624 and rs3176336 with risk of colorectal cancer in an Iranian population. Methods: A case-controls study was conducted to investigate the association of polymorphism rs3176336 and rs762624, with colorectal cancer risk in Iranian population. In this study 150 cases of sporadic CRC and 150 healthy controls were recruited, genomic DNA were extracted from peripheral blood, the genotypes were determined using the polymerase chain reaction and restriction fragment length polymorphism (PCRRFLP) method and the result was validated by direct sequencing. Results: The rs762624 frequencies of the AA, AC, and CC genotypes among cases were 9.3%, 74.7%, and 16%, respectively, while in controls genotype frequencies were 10%, 74%, and 16%, respectively. The rs3176336 frequencies of the AA, AC, and CC genotypes among cases were 29.3%, 18% and 52.7%, respectively, while in controls genotype frequencies were18%, 20%, and 62%, respectively. No association was found for the CDKN1A rs3176336 AT/AA genotype (Adjusted odds ratio (OR), 0.726, 95% confidence interval (CI), 0.365–1.443 for AT genotype; OR, 1.67, 95% CI, 0.754–3.702 for AA genotype) with risk of colorectal cancer, compared with the TT genotype. In our research, we could not found significant relation between stage of colorectal cancer and genotypes of rs762624 and rs3176336 polymorphisms (p=0.081, p=0.988). Conclusion: Present data do not confirm association of rs3176336 and rs762624 polymorphisms with susceptibility of Iranian to colorectal cancer.

Association between the 1793G> A MTHFR polymorphism and sporadic colorectal cancer in Iran.

BACKGROUND: It has been proposed that folate and polymorphisms of the enzyme methylenetetrahydrofolate reductase (MTHFR), which regulates influx of folate for methylation reactions for DNA synthesis and repair, are involved in colorectal cancer. This study was designed to determine the influence of a genetic variant (MTHFR G1793A) and folate on colon cancer in Iran. MATERIALS AND METHODS: We analyzed 227 cases and 239 normal unmatched controls using pyrosequencing. Odds ratios and 95% confidence intervals (95% CI) were calculated to evaluate associations of the MTHFR gene polymorphism with colorectal cancer risk. RESULTS: A significantly reduced risk of recurrence was observed in patients heterozygous for the MTHFR G1793A polymorphism (OR: 0.17; 95% CI, 0.05-0.52). The frequency of GG, GA and AA genotypes of MTHFR among the colorectal cancer patients were 98%, 2% and 0% respectively, while the frequencies among controls were 90%, 10% and 0%, respectively. Furthermore, a significant reduction in recurrence risk was seen in MTHFR G1793A heterozygotes limited to those who received folate supplements. CONCLUSION: Our study is compatible with previous findings concerning a reverse association between the MTHFR 1793G> A genotype with cancers in different populations.

Relation between demographic factors and type of gastrointestinal cancer using probit and logit regression.

BACKGROUND: Approximately 50,000 new cases of cancer occur each year in the Iranian population of 70.4 million. The organ system involved with more than 38% of all cancers is the gastrointestinal (GI) tract. The objective of this study was to investigate the relation between demographic factors and type of gastrointestinal cancer using probit and logit models. METHODS: This study was designed as a cross-sectional survey including all consecutive GI cancer patients admitted over a one year period in a randomly selected hospital group located in Tehran in 2006. RESULTS: The largest number of cases were colorectal cancers (40.0%), followed by gastric cancers (34.5%) and esophagus cancers (17.1%). There was a significant gender effect in the colorectal, gastric and esophagus cancer also there was a significant association between age and gastrointestinal cancers in both logit and probit regression. The factor of duration was not significant in gastric cancer. CONCLUSION: Men are more likely have colorectal cancer than women. Older people are more likely to have gastric cancer than younger people. For esophagus cancer all factors were significant. Results from probit and logit models were similar, indicating that probit analysis can be employed as a logit model to analyze relationships between demographic factors and cancer type.