CDKN1A and tyrosinemia: Staining for p16INK4a and p21cip1 was positive in the explanted liver of the patient with tyrosinemia in the hepatocytes, the canals of Hering, cholangioles and interlobular bile ducts (Fig. 1G–H) In the livers with fulminant hepatitis, p21cip1 staining occurred in the areas of ductal transformation and in the interlobular bile ducts (Fig. 1I; TABLE 2).