Decreased expression of DNA repair genes (XRCC1 and XPD/ERCC2) in colorectal cancer in Iranian patients

摘要

The aim of this study was to investigate the role of the XRCC1 and XPD/ERCC2in the susceptibility and in the progression of colorectal cancer (CRC) in Iranian patients. Epidemiological studies have shown a positive association between defective DNA repair capacity and CRC. The underlying mechanism of their involvement is not wellunderstood. In the present study, we have analyzed the relationship between CRC and the expressionof DNA repair genes namely X-ray repair cross-complementing group 1 (XRCC1) and xeroderma pigmentosum group D (XPD)in 70 formalin fixed and paraffin embedded tumor tissues as well as normal adjacent tissues. The relative expressionof XRCC1and XPDin the mentioned tissues was performed for first time by quantitative real-time PCR (q-PCR). Results of this study demonstrated that difference of mean relative expressionbetween tumor tissues and normal tissues is 64-fold(XRCC1) > 16-fold(XPD). In multivariate logistic regression analysis, low expressionof XRCC1and XPDwas associated with a statistically significant increased risk of CRC [crude odds ratios (ORs) (95%CI) OR 2.10; (1.06-4.17) and OR 5.24 (2.38-11.52), respectively]. In conclusion, our study demonstrated that reduced expressionof XRCC1and XPDis associated with more than twofold increased risk in CRC