We tested the effect of JMJD3/UTX demethylase inhibitor GSK-J4 on five prostate cancer cell lines: R1-AD1 (AR-WT), R1-D567 and R1-I567 (ARΔLBD), CWR22Rv-1 (CRPC cell line that expresses both AR WT and AR with deletion), and PC3 (low levels of AR expression) by the direct cell count after 72h of treatment. This evidence concerns the gene AR and Familial prostate cancer.