Induced tumor cell apoptosis: EGCG triggered programmed cell death in NPC, correlating with suppression of SIRT1 and reactivation of p53 tumor suppressor function. The result is potent anti-tumor activity in vitro, indicating EGCG can target cancer cell survival pathways (like SIRT1) to overcome growth and survival advantages of tumor cells. Here, SIRT1 is linked to cancer.