However, another study showed that SIRT1, as part of the SIRT1/PGC-1α axis, promotes the metastasis of HCC by increasing PGC-1α-mediated mitochondrial biogenesis; a corresponding reduction in the mitochondrial mass and oxidized phosphoric acid caused by low expression of SIRT1 in liver cancer tissues inhibits invasion and metastasis (139). The gene discussed is SIRT1; the disease is liver cancer.