ObjectiveTo systematically review the association between LIG4 gene T9I polymorphism and cancer susceptibility. MethodsSuch databases as PubMed, EMbase, The Cochrane Library (Issue 10, 2013), CBM, CNKI, VIP and WanFang Data were electronically searched to collect case-control studies published up to Oct. 2013 on the association between LIG4 gene T9I polymorphism and cancer susceptibility. According to inclusion and exclusion criteria, two reviewers independently screened literature, extracted data, and assessed methodological quality of included studies. Then meta-analysis was performed using RevMan 5.0 software. ResultsA total of 11 case-control studies were included, which involved 5 016 cancer cases and 4 860 controls. The results of meta-analysis showed that, no significant association was found between LIG4 gene T9I polymorphism and the risk of cancer in the total analysis (TT+CT vs. CC:OR=0.96, 95%CI 0.80 to 1.15, P=0.63; TT vs. CT+CC:OR=1.10, 95%CI 0.78 to 1.56, P=0.59; TT vs. CC:OR=1.10, 95%CI 0.73 to 1.64, P=0.65; CT vs. CC:OR=0.94, 95%CI 0.80 to 1.11, P=0.48; T vs. C:OR=0.97, 95%CI 0.82 to 1.15, P=0.75). In the subgroup analysis, significant association was found in Caucasians (TT+CT vs. CC:OR=0.87, 95%CI 0.77 to 0.98, P=0.02) but not in Asians. ConclusionLIG4 gene T9I polymorphism could be associated with cancer susceptibility in Caucasians.
ObjectiveTo systematically review the association between the IL-6 gene -634G/C polymorphism and the risk of lung cancer. MethodsDatabases including the PubMed, EMbase, CNKI and WanFang Data were searched from inception to October 2015 to collect case-control studies about the correlation between the IL-6 gene -634G/C polymorphism and the risk of lung cancer. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed by using RevMan 5.3 software. ResultsA total of 12 case-control studies concerning 3 657 lung cancer cases and 4 100 controls from 11 articles were included. The results of meta-analysis showed that there was no significant association between the -634G/C polymorphism and the risk of lung cancer (GG+GC vs. CC: OR=1.11, 95%CI 0.89 to 1.39, P=0.37; GG vs. CC+GC: OR=1.17, 95%CI 0.88 to 1.55, P=0.27; GG vs. CC: OR=1.27, 95%CI 0.93 to 1.72, P=0.13; GC vs. CC: OR=1.12, 95%CI 0.89 to 1.40, P=0.33; G vs. C: OR=1.08, 95%CI 0.89 to 1.30, P=0.43). ConclusionIL-6 gene -634G/C polymorphism may not be a risk factor of lung cancer. Due to the limited quality and quantity of included studies, more high quality studies are needed to verify the above conclusion.