CCDC137 and hepatocellular carcinoma: After comparing the mRNA expression levels of P4HA2, CCDC137, NDRG1, and SDC4 between HCC and normal liver tissues, we observed that only the expression levels of P4HA2 were higher and significant in HCC tissues than in normal liver tissues (Fig. 4E), suggesting that P4HA2 is the only potential target of corosolic acid among the 4 candidates.