Lack of Association between an XRCC1 Gene Polymorphism and Colorectal Cancer Survival in Thailand

Abstract

Background: Colorectal cancer (CRC) is one of the most common causes of death worldwide and in Thailand. The X-ray repair cross-complementary protein 1 (XRCC1) is required for efficient DNA repair. The effects of this gene on survival in colorectal cancer remain controversial and have not been reported in Thailand. The aim of this study was to investigate the association of the XRCC1 gene with survival of colorectal cancer patients in a Thai population. Materials and Methods: Data and blood samples were collected from 255 newly diagnosed and pathologically confirmed CRC patients who were recruited during the period 2002 to 2006 and whose vital status was followed up until 31 October, 2014. Real-time PCR-HRM was used for genotype identification. The Kaplan-Meier method, the log-rank test, and Cox proportional hazard regression were used to estimate cumulative survival curves and compare various survival distributions and adjusted hazard ratios. Results: Most of the cases were males, and the median age was 55 years. The median survival time was 2.43 years. The cumulative 1-, 3-, 5-, 7-, and 10 year survival rates were 76.70%, 39.25%, 26.50%, 16.60% and 3.56%, respectively. After adjustment, female gender, ages 50-59 and ≥ 60 years, tumour stage III+IV, a signet-ring cell carcinoma, and poor differentiation had significant associations with increased risk of CRC death. While the XRCC1 Arg/Arg homozygote appeared to be a risk factor for CRC death, the association was not significant. Conclusions: The genetic variant in the XRCC1 may not be associated with the survival of CRC patients in Thailand. Further studies are needed to verify our findings.

Association of XRCC1 Arg399Gln and RAD51 135 G>C Polymorphisms and Epidemiologic Risk Factors with Colorectal Cancer Among Selected Filipinos

“…XRCC1 Arg399Gln has been observed to have no association with survival among Thai CRC patients. 16 In conclusion, XRCC1 Arg399Gln but not RAD51 135G>C may be associated with CRC development among Filipinos. Individuals who drink alcohol, smoke tobacco, and have family history of cancer have a lower risk of developing CRC when they are also carrying the XRCC1 AG genotype.…”

“…Alcohol consumption, tobacco smoking, and family history of cancer have been reported to increase the risk of CRC development. 16,39 Alcohol consumption and smoking have been established as rich sources of reactive oxygen species and chemical carcinogens known to damage DNA. 27,45 Although tobacco smoking has long been known to cause lung cancer; studies show that smoking is also detrimental to the colon and rectum because of its carcinogen content.…”