Lack of associations between XPC polymorphisms and colorectal cancer: a meta-analysis.
AIM To investigate the risk association of xeroderma pigmentosum group C (XPC) Lys939Gln polymorphism alone and in combination with cigarette smoking on colorectal cancer (CRC) predisposition. METHODS Peripheral blood samples of 510 study subjects (255 CRC patients, 255 controls)were collected. DNA was extracted and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. The association between polymorphic genotype and CRC predisposition was determined using the OR and 95%CI. RESULTS The frequency of the homozygous variant (Gln/Gln) genotype was significantly higher in cases compared with controls (16.0% vs 10.2%, P = 0.049). The Gln/Gln genotype of XPC showed a significantly higher association with the risk of CRC (OR = 1.884; 95%CI: 1.082-3.277; P = 0.025). In the case of allele frequencies, variant allele C was associated with a significantly increased risk of CRC (OR = 1.375; 95%CI: 1.050-1.802; P = 0.020). Moreover, the risk was markedly higher for those who were carriers of the Gln/Gln variant genotype and were also cigarette smokers (OR = 3.409; 95%CI: 1.061-10.949; P = 0.032). CONCLUSION The XPC Gln/Gln genotype alone and in combination with smoking increases the risk of CRC among Malaysians.