We confirmed the presence of IL-4 IR in prostate cancer epithelial tissue (Fig. 2A), and found that incubation of both human androgen-insensitive PC-3 cells and rat Dunning R3327 AT-1 prostate cancer cells with IL-4 for 24 h produced a significant increase in FAAH activity of the cells (Fig. 2B and C). Here, FAAH is linked to prostate carcinoma.