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Background: The role of insulin in the pathogenesis of cancer has been increasingly emphasized because of the high incidence of obesity and metabolic syndrome and their correlated complication including cancer. This study aimed to explore the impact of insulin on chemoresistance to 5-fluorouracil in gastric cancer and the possible mechanisms. Methods: Tissue samples of gastric cancer and adjacent normal gastric mucosa from patients with or without obesity were performed immunohistochemical staining for P-glycoprotein. The follow-up was done after the surgical treatment. The effect of insulin on chemotherapeutic sensitivity of the three gastric cancer cell lines to 5-fluorouracil was evaluated by pre-incubation with insulin before administration of 5-fluorouracil. The expression of P-glycoprotein was determined by Western blotting. Results: P-glycoprotein were overexpressed in tissues from patients who suffered gastric cancer and were higher in those simultaneously suffered gastric cancer and obesity. Addition of 1 μM insulin remarkably promoted the proliferation of SGC7901, MKN45 and MKN28 cells and decreased the cytotoxicity of 5-fluorouracil. In addition, the expression of P-glycoprotein was upregulated in SGC7901, MKN45 and MKN28 cells. Conclusion: Insulin improved the proliferation of gastric cancer cell lines and contributed to chemoresistance of gastric cancer cells to 5-fluorouracil which is likely to involve upregulation of P-glycoprotein. [ABSTRACT FROM AUTHOR]

Purpose: We undertook a meta-analysis of randomized trials to evaluate the efficacy of multitargeted antiangiogenic tyrosine kinase inhibitors (MATKIs) in addition to chemotherapy in metastatic breast cancer. Methods: PubMed, Web of Knowledge databases and the ASCO meeting abstracts were searched for eligible literature published up to August 30, 2013. The endpoints included progression-free survival (PFS), overall survival (OS), overall response rate (ORR) and toxicities. Pooled hazard ratios (HRs) for survival outcomes and odds ratio (ORs) for dichotomous data with 95 % confidence intervals (CIs) were derived. Results: Eight studies including 2,077 participants were analyzed. Compared to chemotherapy alone, adding MATKIs to chemotherapy resulted in a 14 % risk reduction of PFS events. However, the benefit did not reach statistical significance (HR 0.86; 95 % CI 0.70-1.04, P = 0.126). Also, no OS benefit was observed (HR 1.03; 95 % CI 0.89-1.18, P = 0.724). The addition of MATKIs significantly increased the ORR (OR 1.57; 95 % CI 1.30-1.91, P = 0.000). Subgroup analysis revealed that sorafinib showed a significantly greater effect on PFS in patients with HER2 negative metastatic breast cancer (HR 0.67; 95 % CI 0.55-0.82, P = 0.000) in comparison to chemotherapy alone. Additionally, sunitinib seemed to have no substantial efficacy for metastatic breast cancer. Toxicities were more frequent in patients receiving MATKIs. Conclusion: Overall, regimens consisting of MATKIs seemed not to be superior to chemotherapy alone in terms of PFS and OS, although significant improvement in ORR was observed. However, the addition of sorafenib significantly improved PFS. Further studies are needed to corroborate this finding. [ABSTRACT FROM AUTHOR]