Bladder cancer is not considered an androgen-driven malignancy, although some experimental models have shown that carcinogenesis can be dependent on AR signaling: wild type animals developed cancer with N-butyl-N-4-hydroxybutyl nitrosamine treatment, but AR knockout mice did not; some of the knockout animals developed cancer after supplementation with dihydrotestosterone, and treatment with flutamide (antiandrogen) suppressed the proliferation of xenograft tumors [14,113]. This evidence concerns the gene AR and cancer.