Objective To investigate the role of platelet-derived growth factor receptor-beta( PDGFR-β) signals in doxorubicin( Dox) resistance of triple-negative breast cancer cell line MDA-MB-231,and explore its underlying mechanism. Methods The percentage of cells arrested at G_2 phase,cell apoptosis and viability were detected by flow cytometry and MTS assay in PDGF-DD( a PDGFR-β specific ligand)incubated cells. The expression levels of mutant p53( mtp53),cdk1,PDGFR-β,p21,bax,hsp90 and TopBP1 were determined by qPC...