PCSK9 and cirrhosis of liver: However, hepatic PCSK9 protein levels in patients (10 HBV, n = 10; HCV, n = 11; nonviral disease etiology, n = 11) with fibrosis stage 1, 2 or 3 were comparable to patients with liver cirrhosis (fibrosis stage 4) [31], indicating that progression of liver cirrhosis may not be accompanied by a continuous lowering of PCSK9 protein levels in the liver.