CDKN2A and hepatocellular carcinoma: Another study also showed that CDKN2A promoter methylation is associated with enhanced HCC risk and plays a key role in the progression of HCC (Zhou et al., 2018); GLS can promote cancer cell metabolism and biogenesis (Huang et al., 2019), and its differential expression can regulate the prognosis of human cancer (Saha et al., 2019); pyruvate dehydrogenase E1α subunit (PDHA1) is one of the main functional enzymes in energy metabolism, and has been considered to be closely related to tumor development and progression (Sun et al., 2019).