Background: Human hepatocellular carcinoma (HCC) is a heterogeneous disease of distinct clinical subgroups. A principal source of tumor heterogeneity may be cell type of origin which in liver includes hepatocyte and/or adult stem/progenitor cells. Objective: To address this issue, we investigated the molecular mechanisms underlying the fate of the enzyme-altered preneoplastic lesions in the resistant hepatocyte (RH) model. Methods: Sixty samples classified as focal lesions, adenoma, early and advanced HCCs were micro-dissected after morphological and immunohistochemical evaluation and subjected to global gene expression profiling. Results: The analysis of progression of the persistent GSTP+ focal lesions to fully developed HCC showed that about 50% of persistent nodules and all HCCs expressed CK19 whereas 14% of remodeling nodules were CK19+. Unsupervised hierarchical clustering of the expression profiles also grouped the samples according to CK19 expression. Further, supervised analysis using the differentially expressed genes in each cluster combined with the gene connectivity tools identified 1308 unique genes and a predominance of the AP-1/JUN network in the CK19+ lesions. In contrast, the CK19-negative cluster exhibited only limited molecular changes (156 differentially expressed genes vs. normal liver) consistent with remodeling towards differentiated phenotype. Finally, comparative functional genomics revealed a stringent clustering of CK19+ early lesions and advanced HCCs with human HCCs characterized by poor prognosis. Furthermore, the CK19 associated gene expression signature accurately predicted the patient survival (P<0.009) and tumor recurrence (P<0.006). Conclusion: Our data establish CK19 as a prognostic marker of early neoplastic lesions and strongly suggest the progenitor derivation of HCC in the rat RH model. The capacity of the CK19 associated gene signature to stratify HCC patients according to clinical prognosis indicates the usefulness of the RH model for studies of stem/progenitor-derived HCC.
Cytokeratin-19, a predictive marker and an early determinant of progenitor-derived hepatocellular carcinoma
LOI, ROBERTO;PERRA, ANDREA;
2010-01-01
Abstract
Background: Human hepatocellular carcinoma (HCC) is a heterogeneous disease of distinct clinical subgroups. A principal source of tumor heterogeneity may be cell type of origin which in liver includes hepatocyte and/or adult stem/progenitor cells. Objective: To address this issue, we investigated the molecular mechanisms underlying the fate of the enzyme-altered preneoplastic lesions in the resistant hepatocyte (RH) model. Methods: Sixty samples classified as focal lesions, adenoma, early and advanced HCCs were micro-dissected after morphological and immunohistochemical evaluation and subjected to global gene expression profiling. Results: The analysis of progression of the persistent GSTP+ focal lesions to fully developed HCC showed that about 50% of persistent nodules and all HCCs expressed CK19 whereas 14% of remodeling nodules were CK19+. Unsupervised hierarchical clustering of the expression profiles also grouped the samples according to CK19 expression. Further, supervised analysis using the differentially expressed genes in each cluster combined with the gene connectivity tools identified 1308 unique genes and a predominance of the AP-1/JUN network in the CK19+ lesions. In contrast, the CK19-negative cluster exhibited only limited molecular changes (156 differentially expressed genes vs. normal liver) consistent with remodeling towards differentiated phenotype. Finally, comparative functional genomics revealed a stringent clustering of CK19+ early lesions and advanced HCCs with human HCCs characterized by poor prognosis. Furthermore, the CK19 associated gene expression signature accurately predicted the patient survival (P<0.009) and tumor recurrence (P<0.006). Conclusion: Our data establish CK19 as a prognostic marker of early neoplastic lesions and strongly suggest the progenitor derivation of HCC in the rat RH model. The capacity of the CK19 associated gene signature to stratify HCC patients according to clinical prognosis indicates the usefulness of the RH model for studies of stem/progenitor-derived HCC.
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