CDKN2A and hepatocellular carcinoma: Consistent with previously published findings in other tumor types in which p16 overexpression has been observed, our immunostaining of an HCC tissue microarray demonstrated that while most HCC samples were negative for p16 staining, all of but one of the tumors with p16 immunoreactivity displayed predominantly cytoplasmic staining, whereas other tumor types on the array displayed a predominantly nuclear staining pattern.