RESEARCH ARTICLE Breast Cancer Anti-Estrogen Resistance 4 (BCAR4) Drives Proliferation of IPH-926 lobular Carcinoma Cells

Background Most breast cancers depend on estrogenic growth stimulation. Functional genetic screen-ings in in vitro cell models have identified genes, which override growth suppression induced by anti-estrogenic drugs like tamoxifen. Using that approach, we have previously identified Breast Cancer Anti-Estrogen Resistance 4 (BCAR4) as a mediator of cell prolifera-tion and tamoxifen-resistance. Here, we show high level of expression and function of BCAR4 in human breast cancer. Methods BCAR4mRNA expression was evaluated by (q)RT-PCR in a panel of human normal tis-sues, primary breast cancers and cell lines. A new antibody raised against C78-I97 of the putative BCAR4 protein and used for western blot and immunoprecipitation assays. Fur-thermore, siRNA-mediated gene silencing was implemented to study the function of BCAR4 and its downstream targets ERBB2/3. Result