Yap Expression is Closely Related to Tumor Angiogenesis and Poor Prognosis in Hepatoblastoma.

Background: Hepatoblastoma (HB) is malignant embryonal tumor typically arising in infants and young children. Yes-associated protein (YAP) is aberrantly activated in various tumors; however, the role of YAP in hepatoblastoma is still unexplored. Methods: We assessed YAP expression in hepatoblastoma using immunohistochemistry. The relationships to clinicopathology and survival were analyzed. Results: Positive rate of YAP expression was higher in hepatoblastoma than in adjacent tissues. YAP overexpression was significantly correlated with lymph node metastasis and vascular invasion. Both epithelial and mixed histological types expressed YAP, but high expression was more frequent in MT. YAP expression correlated with VEGF expression, high microvascular density and low overall survival. Multivariable Cox regression analysis revealed that YAP was an independent prognostic factor for survival in children with hepatoblastoma. Conclusion: In hepatoblastoma, YAP may promote VEGF induced angiogenesis and metastases, with resulting poorer prognosis, representing a potential adverse prognostic marker.