P4HA1 and hepatocellular carcinoma: Due to the low expression level of P4HA2 in the liver under physiological conditions and the significant multiple discrepancies in the molecular level of P4HA2 among cancer and adjacent tissues in HCC compared to P4HA1 [11], the focus is on studying the biological effects and underlying mechanisms caused by abnormally high expression of P4HA2 in HCC [12, 13].