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Accumulating evidence shows that mircroRNAs (miRNAs) play a vital role in tumorigenesis. miR-155 is one of the most multifunctional miRNAs whose overexpression has been found to be associated with different types of cancer including breast cancer. To further determine the potential involvement of miR-155 in breast cancer, we evaluated the expression levels of miR-155 by real-time PCR and correlated the results with clinicopathological features. Matched non-tumor and tumor tissues of 42 infiltrating ductal carcinomas and 3 infiltrating lobular carcinomas were analyzed for miR-155 expression by real-time PCR. Further, we used an antisense technique to inhibit miR-155 expression in vitro. WST-8 test was performed to evaluate cell viability and apoptosis assay was used to investigate the effect of the miR-155 antisense oligonucleotide (miR-155 ASO) on HS578T cell death. The expression levels of miR-155 were significantly higher in tumor tissues than the levels in matched non-tumor tissues (P10%) (P=0.019) and advanced breast cancer TNM clinical stage (P=0.002). Interestingly, we next found that miR-155 expression levels had close relations with ER status (P=0.041) and PR status (P=0.029). Transfection efficiency detected by flow cytometry was higher than 70%, the WST-8 test showed that viability of HS578T cells was greatly reduced after transfection with miR-155 ASO compared with the scramble (SCR) group or the liposome group. The Annexin V-FITC/PI assay also indicated that transfection with miR-155 ASO promoted apoptosis.

The optimal adjuvant treatment modality for gastric cancer has not been well defined. The aim of this study was to evaluate the efficacy and feasibility of adjuvant combined systemic and intraperitoneal chemotherapy (ACSIP) in high-risk patients with locally advanced gastric cancer. Between June 2003 and December 2008, 62 eligible patients with serosa-infiltrating and/or node-positive gastric cancer following curative gastrectomy with D2 lymphadenectomy received ACSIP, consisting of intravenous oxaliplatin 85 mg/m(2) on day 1 followed by leucovorin (LV) 200 mg/m(2) and 5-fluorouracil (5-FU) 450 mg/m(2) on days 1-3, intraperitoneal 5-FU 600 mg/m(2) on days 4-5 and cisplatin (CDDP) 40 mg/m(2) on day 5. Survival rates, the sites of first treatment failure and safety were analyzed. At a median follow-up of 45 months (range 7-101), the 3-year disease-free survival (DFS) and overall survival (OS) rates were 66.1 and 74.2%, respectively. Initial peritoneal and hepatic failures were found in 6 (24.0%) and 3 (12.0%) of the 25 patients with recurrence, respectively. Neutropenia, gastrointestinal side effects and peripheral neuropathy were the most common grade 3-4 toxicities; however, they were all infrequent and manageable. No serious surgical complications or treatment-related mortality was observed. The results of this study indicate that ACSIP is effective and feasible for locally advanced gastric cancer with encouraging survival rates and possibly decreased peritoneal and hepatic recurrences. The benefits of this promising combined adjuvant treatment modality warrant further studies.

Growing evidence suggests microRNAs (miRNAs) have an important role in tumorigenesis. MicroRNA-21 (miR-21) is up-regulated in many malignant tumors, including breast cancer. Its association with clinicopathologic features and expression of PTEN (phosphatase and tensin homolog deleted on chromosome 10), one of its target genes, in breast cancer has not been reported systematically. To further determine the potential involvement of miR-21 in breast cancer, we have evaluated the expression level of miR-21 by stem-loop real-time RT-PCR based on SYBR-Green I in human invasive ductal carcinoma of the breast, and we have correlated the results with clinicopathologic features and PTEN protein expression. Matched non-tumor and tumor tissues of 40 human invasive ductal carcinoma of the breast were analyzed for miR-21 expression by stem-loop real-time RT-PCR based on SYBR-Green I. Immunohistochemistry (IHC) was used to estimate PTEN expression in tumor tissue. The expression levels of miR-21 were correlated with PTEN and commonly used clinicopathologic features of breast cancer. The stem-loop real-time RT-PCR based on SYBR-Green I was sensitive and specific enough to detect miR-21. Expression levels of miR-21 were significantly higher in tumor tissues than the levels in matched non-tumor tissues (P=0.000). Expression of miR-21 was negatively correlated with expression of PTEN (P=0.013). Up-regulated miR-21 expression was associated with lymph node positivity (P=0.01), higher proliferation index (ki67>10%) (P=0.03) and advanced breast cancer TNM clinical stage (P=0.021). These findings suggest that PTEN is possibly one of the targets of miR-21 in breast cancer and high expression of mir-21 indicates a more aggressive phenotype.