In light of our present results which showed that AR-V7 could activate NF-κB with resultant up-regulation of IL-6 and our previous data which showed inhibition of activated NF-κB signaling by melatonin in prostate cancer cells [23], we proceeded to test whether or not melatonin could inhibit the AR-V7-induced IL-6 gene expression in LNCaP and 22RV1 cells. This evidence concerns the gene NFKB1 and prostate carcinoma.