Objective To investigate the effect of tricostantin A(TSA) on self-renewal of breast cancer stem cells and explore the mechanisms. Methods Breast cancer cell lines MDA-MB-468, MDA-MB-231, MCF-7 and SKBR3 were cultured in suspension and treated with different concentrations of TSA for 7 days, using 0.1% DMSO as the control. Secondary mammosphere formation efficiency and percentage of CD44+/CD24-sub-population in the primary mammospheres were used to evaluate the effects of TSA on self- renewal of breast canc...