PECAM1 and hepatocellular carcinoma: In hepatocellular carcinoma (HCC), IER2 [61], PECAM-1 (CD31) can upregulate the expression of ITGB1 [62], while CSN5 can downregulate ITGB1 to promote apoptosis [52], THBS4 can interact with ITGB1 to enhance activation of downstream pathways [63], and circ-PABPC1 can directly mediate the binding of ITGB1 to the proteasome to promote ITGB1 degradation [53].