Polyphenols participate in cancer therapy through a variety of mechanisms, including inhibition of cancer cell proliferation and migration, induction of cancer cell apoptosis, impediment of immunosuppression, etc. For instance, resveratrol inhibited the proliferation and induced apoptosis of human multiple myeloma cell lines by downregulating various proliferative and antiapoptotic gene products, including cyclin D1, cIAP-2, X-linked inhibitor of apoptosis protein (XIAP), survivin, Bcl-2, Bcl-xL, Bfl-1/A1, and TNF receptor associated factor 2 (TRAF2) [56]. Here, XIAP is linked to cancer.