Association between H-RAS T81C genetic polymorphism and gastrointestinal cancer risk: A population based case-control study in China

A population based case-control study, including 296 cases with gastrointestinal cancer and 448 healthy controls selected from a Chinese population was conducted. H-RAS T81C polymorphism was genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay.In the healthy controls, the TT, TC and CC genotypes frequencies of H-RAS T81C polymorphism, were 79.24%, 19.87% and 0.89%, respectively, and the C allele frequency was 10.83%. Compared with TT genotype, the TC genotype was significantly associated with an increased risk of gastric cancer (adjusted OR = 3.67, 95%CI = 2.21–6.08), while the CC genotype showed an increased risk as well (adjusted OR = 3.29, 95%CI = 0.54–19.86), but it was not statistically significant. In contrast, the frequency of TC genotype was not significantly increased in colon cancer and rectal cancer patients. Further analysis was performed by combining TC and CC genotypes compared against TT genotype. As a result, a statistically significant risk with adjusted OR of 3.65 (95%CI, 2.22–6.00) was found in gastric cancer, while no significant association of H-RAS T81C polymorphism with colon cancer and rectal cancer was observed.These findings indicate, for the first time, that there is an H-RAS T81C polymorphism existing in Chinese population, and this SNP might be a low penetrance gene predisposition factor for gastric cancer.Gastrointestinal cancer, including cancers of the oesophagus, stomach, small intestine, colon, rectum and liver etc, is a major medical and economic burden worldwide. Although the incidence and mortality of gastrointestinal cancer has been gradually decreasing for decades, some common types of gastrointestinal cancer are steadily in the top five leading cause of new cancer cases and deaths, such as gastric cancer, colon and rectal cancer[1]. Multiple factors have been proposed to play important roles in human carcinogenesis, however, the exact mechanism of gastrointestinal cancer development