G-protein Coupled Estrogen Receptor 1 Expression in Primary Breast Cancers and Its Correlation with Clinicopathological Variables.

PURPOSE: G-protein coupled estrogen receptor 1 (GPER) probably play important roles in the progression of breast cancer including endocrine therapeutic resistance. We evaluated GPER in primary breast cancers. METHODS: Immunohistochemistry was used to detect GPER in paraffin-embedded tissues of primary breast cancers from 423 patients and GPER expression was correlated with clinicopathological factors. RESULTS: GPER was expressed in 63.8% of specimens, coexpressed with estrogen receptor alpha (ERα) in 36.6% of tumors and was positive in 62.5% of the ERα-negative tumors. The expression of GPER had no relationship with the status of ERα, progesterone receptor and HER2. Although the expression of GPER was significantly inversely related with nodal status (p=0.045), no correlation between GPER expression and other clinicopathological variables (age, menstruation status, tumor size, stage, histologic grade, Nottingham Prognostic Index or pathological type) was found. CONCLUSION: GPER and ERα exhibited independent expression pattern of distribution in primary breast cancers. A long-term follow-up and a more definite molecular phenotype for ER are necessary in confirming studies.

The let-7a microRNA protects from growth of lung carcinoma by suppression of k-Ras and c-Myc in nude mice.

PURPOSE: Down-regulation of let-7 microRNA (miRNA) plays an important role in the pathogenesis of lung cancer. k-Ras and c-Myc, two key oncogenes in lung cancer, have been found to be targeted by let-7 in vitro. However, the in vivo relevance of these findings is unknown. The aim of the present study is to determine the effect of let-7a, a member of let-7 family, on the growth of lung cancer in vivo and to investigate whether let-7-induced suppression of k-Ras and c-Myc is involved in lung cancer. METHODS: A549-let-7a cell line and A549-control cell line, two stable transfected cell lines over-expressing let-7a and the control miRNA, were established and preserved in our lab. A549, A549-control, and A549-let-7a cells were injected subcutaneously into nude mice, respectively. After 30 days, the mice were killed; the xenografts were excised and weighed. The expression of let-7a in tumor xenografts was assessed by real-time reverse transcription-PCR (RT-PCR). The expression of k-Ras and c-Myc in xenografts were determined by western blot and immunohistochemistry detection. RESULTS: Real-time RT-PCR showed the expression of let-7a was increased significantly in A549-let-7a cells-injected group, compared with A549-control cells-injected group and A549 cells-injected group (P < 0.01). In the xenografts of A549-let-7a cells-injected group, a significant depression in tumor weight (P < 0.05) and significant decrease of k-Ras and c-Myc protein were observed (P < 0.01), compared to A549 cells-injected group and A549-control cells-injected group. CONCLUSION: Overexpression of let-7a can inhibit the growth of lung cancer transplanted subcutaneously in nude mice by suppression of k-Ras and c-Myc.