Comparison of hepatocellular carcinoma in American and Asian patients by tissue array analysis

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Although some epidemiologic and etiologic differences between Asian and Western HCC are known, detailed comparative studies with pathologic correlations have not been performed. Methods: Paraffin sections of resected HCC specimens from Memorial Sloan-Kettering Cancer Center and Korea University Medical Center were used to construct tissue microarrays. Immunohistochemical staining of microarray sections was performed using antibodies against markers of proliferation and regulators of cell cycle. Patient data were correlated with staining results. Results: When comparing both cohorts, significant differences were found in expression of p53 and MDM2. In the Asian group, more frequent positive staining for p53 (24%) was observed compared with the American group (9%; P = 0.037). For MDM2, 26% of American cases stained positive compared with 2% of Asian cases (P = 0.0003). No significant differences were found in expression of Ki67, p21, p27, cyclin D1, or bcl2. Female gender, vascular invasion, and lack of viral hepatitis infection correlated with positive MDM2 staining. Conclusion: These data likely correlate with differences in molecular pathogenesis of HCC based on racial and regional differences. These findings may have implications in choice of molecular targeted therapies based on patient ethnicity.