ObjectiveTo investigate PTEN expression and its relationship with clinicopathologic features in patients with gastric cancer. MethodsWe searched published studies in PubMed, EMbase, CNKI, VIP, WangFang Data and CBM from the day of establishment to July 24th, 2013. Some other relevant references were also searched to collect all the case-control studies. Two reviewers independently screened studies according to the inclusion and exclusion criteria, extracted data and assessed quality of the included studies independently. Then meta-analysis was conducted using RevMan 5.2 software. ResultsA total of 14 studies were recruited, which included 1 026 cases in the gastric cancer group and 539 cases in the normal gastric mucosa group. The results of meta-analysis showed that PTEN expression was lower in the gastric cancer group than in the normal gastric mucosa group, with a significant difference[OR=0.07, 95%CI (0.05, 0.10), P<0.000 01]. No significant difference was detected in age[OR=1.34, 95%CI (0.88, 2.04), P=0.17] and sex[OR=0.91, 95%CI (0.60, 1.36), P=0.64]. There were significant differences in terms of tumor length[OR=3.67, 95%CI (2.02, 6.67), P<0.000 1], histologic subtype[OR=3.54, 95%CI (2.56, 4.91), P<0.000 01], invasion depth[OR=3.36, 95%CI (2.41, 4.67), P<0.000 01], lymphatic metastasis[OR=4.11, 95%CI (2.98, 5.67), P<0.000 01], and TNM stage[OR=3.94, 95%CI (2.74, 5.65), P<0.000 01]. ConclusionPTEN expression reduces in gastric cancer, and its lower expression increases malignant behaviors of gastric cancer.
ObjectiveTo systematically review the association between -765 G > C (rs20417) polymorphism of cyclooxygenase-2 (COX-2) gene and the risk of gastric cancer (GC). MethodsSuch databases as PubMed, EMbase, The Cochrane Library (Issue 10, 2015), CBM, CNKI, VIP and WanFang Data were searched from inception to October 2015 to collect case-control studies about the correlation between -765 G > C (rs20417) polymorphism of COX-2 gene and GC. Two reviewers independently screened literature, extracted data and evaluated the quality of included studies. Meta-analysis was performed using Stata 12.0 software. ResultsA total of 15 case-control studies were included in this meta-analysis, including 2 891 cases and 4 967 controls. Meta-analysis showed that the -765 G > C (rs20417) polymorphism was significantly associated with the risk of GC (OR=1.70, 95%CI 1.21 to 2.38, P=0.002). Subgroup analysis showed there was a significant association between the -765 G > C (rs20417) polymorphism and GC in Asians (OR=2.24, 95%CI 1.70 to 2.96, P=0.000); However, no association was found in the Caucasians and Americans. In the subgroup analysis by Helicobacter pylori (H. pylori) status, there were statistical significances between helicobacter pylori (+) and helicobacter pylori (-) with the risk of GC in COX-2 polymorphism of CC/CG vs. GG (OR=2.11, 95%CI 1.41 to 3.14, P < 0.001). ConclusionThe COX-2-765 G > C (rs20417) polymorphism may be significantly associated with an increased risk of GC, especially among Asians.
ObjectiveTo evaluate the relationship between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and efficacy of fluorouracil-based chemotherapy in patients with advanced gastric cancer (AGC). MethodsComputer retrieval in China Journal Full-text Database, Chinese Science and Technology Periodical Database, Wanfang database, Chinese Biomedical Literature Database, PubMed, EMbase, Cochrane Library and Web of Science Database (from their establishment to May 28, 2013) was performed to include case-control studies on MTHFR gene C677T polymorphism and sensitivity to fluorouracil-based chemotherapy in patients with advanced gastric cancer. Statistical analysis was done by using RevMan 5.1 software. ResultsSeven case-control studies with 775 patients were included. The meta-analysis showed that among MTHFR C677T genotypes, for TT vs. CC, OR=4.63, 95%CI (1.23, 17.4); and for CC+CT vs. TT, OR=0.21, 95%CI (0.06, 0.78). Subgroup analysis of Asian group showed that for TT vs. CC, OR=32.99, 95%CI (11.40,95.42); and for CC+CT vs. TT, OR=0.04, 95%CI (0.02, 0.10). Sensitivity analysis performed according to different detection methods showed that for TT vs. CC, OR=6.03, 95%CI (1.53, 23.72); and for CC+CT vs.TT, OR=0.17, 95%CI (0.04, 0.68). ConclusionPolymorphism of MTHFR C677T gene may be associated with sensitivity to fluorouracil-based chemotherapy in patients with AGC.