RT Journal Article SR Electronic T1 Effects of Estrogen on Apoptotic Pathways in Human Breast Cancer Cell Line MCF-7 JF Cancer Research JO Cancer Res FD American Association for Cancer Research SP 2487 OP 2489 VO 55 IS 12 A1 Wang, Thomas T. Y. A1 Phang, James M. YR 1995 UL http://cancerres.aacrjournals.org/content/55/12/2487.abstract AB We utilized a reverse transcription-PCR method to examine the effect of estrogen on the expression of mRNA for Bcl-2 and Bax, two modulatory proteins in the apoptotic pathway, in human breast cancer cell line MCF-7. We found that the bcl-2 mRNA levels in the cells exposed to 17β-estradiol were higher than those of control cells. Although the relative bax mRNA levels remained unchanged, the changes in bcl-2 mRNA level occurred in a time- and concentration-dependent fashion. In addition, pretreatment with 17β-estradiol protected MCF-7 cells from apoptosis. Our study provides evidence that responses of breast epithelial cells toward a steroid sex hormone involve regulation of the apoptotic pathway. ©1995 American Association for Cancer Research.