Impact of the cyclin D1 A870G polymorphism on susceptibility to sporadic colorectal cancer in Taiwan

PURPOSE: Cyclin D1 is a regulatory protein involved in the cell cycle of both normal and neoplastic cells. Polymorphism of this gene at codon 242 in exon 4 has impacts on risk of the early-age onset in several malignant neoplasms, including colorectal cancer. This investigation was designed to evaluate the effect of cyclin D1 gene polymorphism on the risk of colorectal cancer in Chinese migrants of the Taiwanese population. METHODS: We enrolled 831 primary sporadic colorectal cancer patients as the study group and 1,052 age-gender matched healthy individuals as the control group (1,883 total cases) for present study. Cyclin D1 genotypes (AA, AG, GG) were determined using PCR-RFLP analysis on genomic DNA. RESULTS: The frequency of G allele was 39.89 percent and 40.96 percent in the study group and the control group, respectively (P = 0.02). The patients were divided into three age groups for statistical analysis. The younger male patients had a higher frequency of AA/AG genotype compared with the controls (odds ratio, 2.75; 95 percent confidence interval, 1-7.9). The effect of AA/AG genotype on colorectal cancer risk was statistically significant for male patients (odds ratio, 1.34; 95 percent confidence interval, 1.04-1.72), but such phenomenon was not observed in female patients. CONCLUSIONS: Our study suggests that the effect of cyclin D1 gene polymorphism on colorectal cancer risk is only observed in males and AA/AG genotype of cyclin D1 gene is associated with a higher risk of colorectal cancer in the younger patients within the Taiwanese population.