XPC Lys939Gln polymorphism, smoking and risk of sporadic colorectal cancer among Malaysians

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.

DNA修复基因XPCAla499Val、Lys939Gln多态与肺癌易感性

目的探讨中国人DNA修复基因XPCAla499Val、Lys939Gln多态与肺癌易感性的关系。方法以社区为基础的病例对照研究。经组织学确诊的肺癌病例320例,相同地区年龄和性别频数匹配的人群对照322人,以PCR为基础的方法进行多态性检测,比较不同基因型与肺癌风险的关系,并探讨吸烟在其中的影响。结果与携带499Ala/Ala基因型者比较,携带至少1个499Val等位基因者(即Ala/Val和Val/Val基因型)肺癌风险增加1.54倍(95%CI=1.11～2.14),而同时有499和939两个位点变异等位基因者肺癌风险增加2.55倍(95%CI=1.45～4.52)。交互作用分析显示,XPC499Val变异基因型与吸烟具有超相乘模型的交互作用,同时有两个位点变异等位基因并吸烟者肺癌风险增加可高达7.36倍(95%CI=3.19～17.0)。结论XPCAla499Val和Lys939Gln多态可能与中国汉族人群肺癌遗传易感性有关,并可显著增加吸烟对肺癌的危险性。