ITGA6 and Familial prostate cancer: To investigate whether exogenous estrogens play a role in prostate cancer, we used flow cytometry to detect the expression of CD49f in androgen independent PCa cell lines, LNCaP-abl and PC3, the results showed that CD49f-positive cells were significantly increased after treatment with E2 (Fig. 1d), and the results of enriched stem cell spheres of LNCaP-abl (PCSCs) treated with E2 showed that both the number and diameter of stem cell spheres was increased following treatment with E2 (Fig. 1e, f).