PCSK9 and familial hypercholesterolemia: Of note, PCSK9, which stands for the up-regulation of LDL cholesterol via promoting LDL receptor degrading, may participate in cancer progression by modulating cholesterol supply to the tumor, as indicated in a B cell tumor mouse model in which hepatic PCSK9 expression and secretion were induced, leading to hepatic LDLR reduction and hypercholesterolemia.