Biology of Human Tumors

Purpose: Tumor differentiation is a behavioral index for hepatocellular carcinoma (HCC) and a prognostic factor for patients with HCC who undergo orthotopic liver transplantation (OLT). However, the molecular basis for HCC differentiation and prognostic value of the underlying molecules that regulate HCC differentiation are unclear. In this study, we defined a potential driver pathway for HCC differentiation and prognostication. Experimental Design: The regulation and function of Kr€ uppellike factor 4 (KLF4) and hepatocyte nuclear factor-6 (HNF-6) in HCC differentiation was evaluated using human tissues, molecular and cell biology, and animal models, and its prognostic significance was determined according to its impact on patient survival. Results: There was a direct relationship between the expression levels of KLF4 and HNF6 in HCC. Reduced KLF4 or HNF6 expression correlated with high HCC grade. Poorly differentiated HCC cells had lower expression of KLF4 or HNF6 and differentiation-associated markers than did well-differentiated cells. Elevated KLF4 of HNF6 expression induced differentiation of poorly differentiated hepatoma cells. Mechanistically, KLF4 trans-activated HNF-6 expression. Restored HNF-6 expression upregulated expression of differentiation-associated markers and inhibited HCC cell migration and invasion, whereas HNF-6 knockdown did the opposite. Loss of KLF4 expression in primary HCC correlated with reduced overall survival and shortened relapsefree survival durations after OLT. Combination of KLF4 expression and the Milan criteria improved prognostication for HCC after OLT. Conclusions: The dysregulated KLF4/HNF-6 pathway drives dedifferentition andprogression ofHCC, andKLF4 is a biomarker for accurate prognostication of patients with HCC treated by OLT when integrated with the Milan Criteria. Clin Cancer Res; 22(2); 502–12. 2015 AACR.