The present invention addresses the problem of providing an efficacious and novel therapeutic method for androgen-dependent prostate cancer and providing a marker that is useful in predicting an effect of a treatment on castration resistant prostate cancer. A double-stranded nucleic acid molecule such as siRNA capable of suppressing the expression of ABHD2 gene is prepared and the progress of androgen-dependent prostate cancer is suppressed thereby. By using the expression of ABHD2 gene as a determination marker, an effect of a treatment on castration resistant prostate cancer is preliminarily predicted.
