In breast and prostate cancer cells, 6-shogaol downregulates STAT3-regulated gene expression by inhibiting the group activation of STAT3, including Bcl- xl, Bcl-2, IAP-1, survivin, cyclin D1, MMP-9 and COX-2, thereby inhibiting cell proliferation, leading to G1-G0 phase arrest and inducing cell apoptosis. This evidence concerns the gene STAT3 and prostate cancer.