OBJECTIVETo analyze the relationship between estrogen dependence of breast cancer cells and expression level of PC-cell derived growth factor (PCDGF) and investigate the possibility of practicing endocrine therapy in estrogen receptor negative breast cancer.

METHODSExpression level of PCDGF mRNA was detected by fluorescence quantitative polymerase chain reaction and cell growth curve was drawn by cell count kit-8 method, then analyzed the relationship between the expression of PCDGF and dependence of estrogen. PCDGF shRNA vector was constructed and transfected into breast cancer cell lines (MCF-7 and MDA-MB-231) using Lipofectamin 2000, examined and compared the changes of estrogen dependence between the two cell lines.

RESULTSPCDGF was expressed in most breast cancer cell lines, and the growth dependence of estrogen was higher in the cells with high-expressing PCDGF than those with low-expressing PCDGF. Expression of PCDGF could be inhibited by transfected shRNA into MCF-7 and MDA-MB-231 (inhibition rates were 81.1% and 86.7% respectively), inhibition of the expression of PCDGF could lead to higher growth dependence of estrogen, and the dependence of MDA-MB-231 was increased much more than MCF-7(P < 0.05).

CONCLUSIONSThe expression level of PCDGF is higher in estrogen receptor negative breast cancer than in estrogen receptor positive breast cancer. Inhibiting the expression of PCDGF could reverse resistance of endocrine therapy especially to estrogen receptor negative breast cancer.