35 have identified the dominant negative mutant of ARA54 inhibiting androgen receptor‐mediated prostate cancer cell growth. The only difference from the non‐mutant ARA54 sequence was a point mutation within the Hsp70/Hsp90‐like motif at the C terminus changing a glutamate residue to lysine 35. Here, HSP90AB1 is linked to Familial prostate cancer.