Presented is a therapeutic method to treat prostate carcinomas in mammals comprising the administration of cellular PAcP protein. Also presented is a method to diagnose androgen-insensitive prostate carcinomas by determining the expression level of cellular PAcP in the prostate carcinomas, a decrease in expression being indicative of androgen-insensitivity. A promoter region that is specifically expressed in prostate tissue is presented, as is a xenograft animal model that mimics human prostate carcinomas in the expression of cellular PAcP.