Expression features and prognostic significance of Yes-associated protein in hepatocellular carcinoma and cholangiocellular carcinoma

Objective To investigate the expression of Yes-associated protein (YAP) in hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CC) and its association with clinical prognosis.Methods Samples were collected from 190 patients who were treated in The Second Hospital Affiliated to Chongqing Medical University from July 2004 to July 2009, among whom 110 had HCC and 80 had CC.The difference in YAP expression and its association were analyzed in both groups, and patients' prognosis was compared between the two groups.The chi-square test was used to investigate the association between YAP expression and clinicopathological features of HCC and CC, and the Kaplan-Meier method and the log-rank test were used to assess tumor-free survival rate and overall survival rate.A univariate Cox regression analysis was used to evaluate the influence of YAP expression on the prognosis of patients with HCC and CC.Results The CC group had higher expression of YAP than the HCC group (68.7% vs 56.3%, P=0.036) .High YAP expression in HCC and CC was significantly associated with tumor size (P<0.001 and P=0.024) , alpha fetoprotein (P=0.009 and 0.034) , liver cirrhosis (P=0.032 and 0.006) , vascular invasion (P=0.011 and 0.028) , and intrahepatic metastasis (P=0.049 and 0.030) .In both groups, the patients with high YAP expression had significantly lower tumor-free survival rate and overall survival rate than those with low YAP expression (all P<0.05) .Multivariate analysis showed that high YAP expression is an adverse prognostic factor for tumor-free survival and overall survival in both groups (all P<0.05) .Conclusion High YAP expression is frequently found in patients with HCC and CC, and high YAP expression is associated with low survival rate.