699 Liver Transplantation and Survival in Patients With Hepatocellular Carcinoma and Tumor Size Larger Than Milan Criteria: UNOS Database Analysis

Abstract

Background and aims: Recurrence and metastasis remain the most common lethal outcomes of hepatocellular carcinoma (HCC) after curative resection. Thus it is critical to reveal the mechanism underlying HCC metastasis. Forkhead box C1 (FoxC1), a member of Fox transcription factor family, has recently been shown to be closely associated with the progression and worse prognosis of human breast cancer. However, whether or not FoxC1 contributes to the progression of HCC remains unknown. We hypothesize that FoxC1-induced epithelial-mesenchymal transition (EMT) plays a key role in HCC metastasis. Methods: This study employed a tissue microarray containing samples from 406 HCC patients who underwent curative resection to examine the expression of FoxC1 and its correlation with clinicopathological characteristics. A series of In Vivo and In Vitro assays were performed to elucidate the function of FoxC1 in HCC and its underlying mechanisms. Results: FoxC1 was markedly higher in HCC tissues than in adjacent noncancerous tissues. FoxC1 overexpression was correlated with multiple malignant characteristics including tumor number, maximal tumor size, microvascular invasion, differentiation status, and tumor-node-metastasis stage. Kaplan-Meier analysis showed that patients with HCC who had positive FoxC1 expression had worse prognosis than those with negative FoxC1 expression. Furthermore, multivariate analysis revealed that the FoxC1 expression level was an independent and significant risk factor for recurrence and survival after curative resection. Overexpression of FoxC1 in human HCC cells induced changes characteristic of EMT, including upregulation of mesenchymal markers, downregulation of epithelial markers, and an increase in cell migration and invasion. FoxC1 transactivated Snai1 expression through directly binding to its promoter, thereby leading to the inhibition of E-cadherin transcription. Conversely, inhibition of FoxC1 resulted in downregulation of mesenchymal markers and loss of cell invasion and reduced the ability of human HCC cells to form lung metastasis in a xenograft model. Knockdown of Snai1 significantly attenuated FoxC1-enhanced invasion In Vitro and lungmetastasis In Vivo. Immunohistochemistry revealed that FoxC1 expression was positively correlated with Snai1 expression, but inversely correlated with E-cadherin expression. Kaplan-Meier analysis showed that patients with FoxC1(+)/Snai1(+) coexpression had shorter overall survival and higher recurrence rates than those with FoxC1(-)/Snai1(-) coexpression. Simarily, patients with FoxC1(+)/E-cadherin(-) expression had shorter overall survival and higher recurrence rates than those with FoxC1(-)/E-cadherin(+) expression. Conclusions: FoxC1 may promote HCC metastasis through the induction of EMT process and may be a candidate biomarker for prognosis as well as a target for therapy.