Despite medical or surgical castration, tumor levels of androgens in human prostate samples, in particular DHT, have been shown to remain at levels sufficient to transactivate the AR in cell line studies.[20] Although serum testosterone is reduced by 95% following castration, tissue levels of DHT remain as high as 40%[21] suggesting that through intracrine processing within the prostate, adrenal androgens are transformed into the 10 times more potent DHT[20] [Figure 3]. The gene discussed is AR; the disease is neoplasm.