HOXB13 and Familial prostate cancer: In line with these previous data, results from this study demonstrated that ATRA was able to induce growth arrest of two AR− prostate cancer cells DU145 and PC-3 in a dose-dependent manner (Fig. 1A and Fig. S1), and this effect was partially achieved through promoting HOXB13 mRNA and protein production (Fig. 1C and S2, S3).