ARID4B and Familial prostate cancer: To demonstrate the effects of ARID4B ablation on prostate tumorigenesis driven by PTEN deficiency in mice, we used the well-characterized prostate cancer mouse model that carries prostate-specific deletion of Pten (PtenPC−/−), and generated mice carrying prostate-specific deletions of both Pten and Arid4b (PtenPC−/−Arid4bPC−/−) (Supplementary Fig. 7a).