It has been shown that the P53/miR-34a/SIRT1 positive feedback loop is activated according to severity of human non-alcoholic fatty liver disease (NAFLD), and several antitumor drugs could activate the P53/miR-34a/SIRT1 positive feedback loop in cancer cell lines to induce the apoptosis of cancer cells [26, 27]. Here, SIRT1 is linked to cancer.