AIM: To detect the expression of WNT5B in normal breast epithelial cells and different breast cancer cell lines, and to investigate the effects of WNT5B over-expression on the viability and apoptosis of human breast cell line MCF-7.METHODS: The mRNA expression of WNT5B was detected by RT-PCR in different breast cancer cells. MCF-7 cells were transfected with plasmid pcDNA3.1 /WNT5B or pcDNA3.1, and the expression of WNT5B at mRNA and protein levels was examined in the 2 groups by real-time PCR and Western blotting, respectively.Subsequently, the chan-ges of cell viability and cell apoptosis were analyzed by CCK-8 assay and flow cytometry, respectively.RESULTS: The ex-pression of WNT5B in the breast cancer cell lines was lower than that in MCF10A cells.The WNT5B expression in the MCF-7 cells in experimental group was significantly higher than that in vector group (P <0.05).However, the cell viabili-ty in experimental group decreased significantly as compared with vector group (P <0.05).The number of the cells in S-phase obviously increased, while the percentage of the cells in G1-phase and G2 /M-phase decreased compared with vector group.The number of apoptotic cells in WNT5B group was significantly higher than that in vector group.CONCLUSION:The expression of WNT5B is decreased in breast cancer cells.WNT5B over-expression significantly inhibits the cell growth and promotes the cell apoptosis in breast cancer MCF7 cells.

[ ABSTRACT] AIM:To study the expression of WNT5B in the breast cancer and further to discuss the correlation between WNT5B and clinicopathologic characteristics of breast cancer.METHODS:The expression of WNT5B at mRNA and protein levels was measured by real-time PCR and Western blot in 67 cases of breast cancer and the tissue adjacent to carcinoma.In addition, the immunohistochemical method was used to detect the expression of WNT5B in the breast cancer and the tissue adjacent to carcinoma.The relationships between WNT5B expression and clinicopathologic indexes were also analyzed.RESULTS:The expression of WNT5B in the breast cancer was obviously lower than that in the tissue adjacent to carcinoma (P<0.05).The expression of WNT5B at mRNA and protein levels in 67 samples of breast cancer was in va-rious degrees.The expression of WNT5B in T≤20 mm group of human breast cancer was obviously higher than that in T>20 mm group (P<0.05).The expression of WNT5B had no obvious correlation with axillary lymph node metastasis, histo-logical grade and immunohistochemical indexes of ER, PR, c-ErBb-2, p53 and Ki67 ( P>0.05) in the breast cancer. CONCLUSION:The expression of WNT5B decreases obviously in breast cancer.The expression of WNT5B is related to primary tumor size, which provides new ideas for the diagnosis and treatment of breast cancer, suggesting that WNT5B may be a new molecular marker for prognosis of breast cancer.