CDKN2A and Hepatic fibrosis: While samples (n = 45) without significant liver fibrosis (F0 to F2) expressed no p16 (mean IRS: 0.36), immunostaining was significantly enhanced in samples (n = 30) with advanced liver fibrosis or cirrhosis (F3 to F6) (mean IRS: 2.6) (p < 0.01) (Figure 5).