Abstract: The Correlation between the Expression of Tumor Suppressor Gene RSK4 and theInvasiveness of Breast Cancer Cell Lines in vitroXiaoli ZHANG1, Jianlun LIU1, Huawei YANG1,WeiWEI1, Yi JIANG1, Dezhong Joshua Liao2Correspondence to: Jianlun LIU, E-mail: jianlunliu@hotmail.com1Breast Diseases Center, Guangxi Medical University Affiliated Tumor Hospital, Nanning 530021, China2Translational Cancer Research Section, Hormel Institute of Minnesota University, Austin MN55912, USAThis work was supported by National Natural Science Foundation of China (No.30960427)Abstract Objective: To detect the expression of RSK4 mRNA in MDA-MB-231, T47D, Bcap37 and MCF-7 breast cancer celllines, and to analyze the relationship between this expression and the invasion of the cell lines in order to investigate the mechanism ofRSK4 inhibition. Methods: RT-PCR was used to verify the mRNA level of expression of RSK4. Cell migration and invasion abilitieswere measured by Transwell chamber, and then the relationship between the cell migration ability and RSK4 gene was analyzed. Re-sults: Cell migration and invasion abilities in the four cell lines was MDA-MB-231 > T47D > Bcap-37 > MCF-7 ( P < 0.001 ). The in-vasiveness and migration presented with a positive correlation ( r = 0.822, P < 0.001 ). The expression of RSK4 mRNA in the four dif-ferent breast cancer cell lines was MDA-MB-231 < T47D