Association between the MTHFR C677T polymorphism and risk of cancer: evidence from 446 case-control studies.

Many molecular epidemiological studies have been performed to explore the association between MTHFR C677T polymorphism and cancer risk in diverse populations. However, the results were inconsistent. Hence, we performed a meta-analysis to investigate the association between cancer risk and MTHFR C677T (150,086 cases and 200,699 controls from 446 studies) polymorphism. Overall, significantly increased cancer risk was found when all eligible studies were pooled into the meta-analysis. In the further stratified and sensitivity analyses, significantly increased breast cancer risk was found in Asians and Indians, significantly decreased colon cancer risk was found, significantly decreased colorectal cancer risk was found in male population, significantly increased gastric cancer risk was found in Caucasians and Asians, significantly increased hepatocellular cancer risk was found in Asians, significantly decreased adult acute lymphoblastic leukemia (AALL) risk was found in Caucasians, significantly decreased childhood acute lymphoblastic leukemia (CALL) risk was found in Asians, and significantly increased multiple myeloma and NHL risk was found in Caucasians. In summary, this meta-analysis suggests that MTHFR C677T polymorphism is associated with increased breast cancer, gastric cancer, and hepatocellular cancer risk in Asians, is associated with increased gastric cancer, multiple myeloma, and NHL risk in Caucasians, is associated with decreased AALL risk in Caucasians, is associated with decreased CALL risk in Asians, is associated with increased breast cancer risk in Asians, is associated with decreased colon cancer risk, and is associated with decreased colorectal cancer risk in male population. Moreover, this meta-analysis also points out the importance of new studies, such as Asians of HNC, Asians of lung cancer, and Indians of breast cancer, because they had high heterogeneity in this meta-analysis (I(2) > 75%).

Pemetrexed is mildly active with good tolerability for treatment of patients with colorectal cancer.

PURPOSE: This systematic analysis was conducted to evaluate the efficacy and safety of pemetrexed based salvage chemotherapy for treatment of patients with metastatic colorectal cancer. METHODS: Clinical studies evaluating the efficacy and safety of pemetrexed based regimens on response and safety for patients with colorectal cancer were identified using a predefined search strategy. Pooled response rates (RRs) were calculated. RESULTS: For pemetrexed based regimens, 4 clinical studies including 201 patients with advanced colorectal cancer were considered eligible for inclusion. The analysis suggested that, in all patients, pooled RR was 20.4% (41/201). Major adverse effects were neutropenia, anorexia, fatigue, and anemia. No treatment related death occurred with pemetrexed based treatment. CONCLUSION: This systematic analysis suggests that pemetrexed based regimens are associated with mild activity with good tolerability in treating patients with metastatic colorectal cancer.