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). This evidence concerns the gene PPARGC1A and liver cancer.