Absence of CD66a expression is associated with high microvessel density and high histologic grade in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver. Patients with HCC usually have poor prognosis and high mortality. It has been shown that carcinoembryonic antigen-related cell adhesion molecule 1 (CD66a) regulates cell signaling, proliferation, and tumor growth. The aim of this study is to analyze the expression and possible role of CD66a in HCC. Immunohistochemical staining of CD66a was performed on 86 HCC cases, and microvessel density was evaluated by CD34 immunostaining. The results were further correlated with clinicopathological parameters. For 47 of 86 HCC cases, the CD66a expression showed diffuse membrane or cytoplasmic staining. The other 39 HCC cases revealed loss of CD66a expression. Loss of CD66a expression was statistically significantly associated with large tumor size (p = 0.016), fatty change (p = 0.039), patients with transcatheter arterial embolization (p = 0.007), and high microvessel density (p = 0.036). CD34 expression had no significant association with tumor size, virus infection, histological grade, and capsular invasion. The diffuse and cytoplasmic expression of CD66a may involve the early stage of the HCC, and the loss of CD66a expression indicates tumor progression.