Significance of immunohistochemical over-expression of CD44v6 as an indicator of malignant potential in esophageal squamous cell carcinoma

Purpose. The aim of the current study was to find out a clinicopathologic significance of CD44v6 over-expression in esophageal squamous cell carcinoma (ESCC), which has not been elucidated fully. Methods. Immunohistochemical expression of CD44v6 was examined for 81 ESCCs. Correlation of CD44 over-expression with the clinicopathologic features were investigated. Results. Thirty-eight ESCCs (46.9%) had over-expression of CD44v6. The proportions of the incidence of lymph node metastasis (P=0.039), lymphatic permeation (P=0.003), and blood vessel invasion (P=0.037) in ESCCs with over-expression of CD44v6 were significantly higher than those in ESCCs without over-expression of CD44v6. The stage of the tumor in ESCCs with over-expression of CD44v6 was significantly more advanced (P=0.045). Survival rates of patients with ESCC with over-expression of CD44v6 were significantly worse (P=0.0005). Moreover, CD44v6 over-expression (P=0.048) as well as blood vessel invasion (P=0.014) and stage of the tumor (P=0.010) were factors independently associated with the unfavorable prognosis of the patients with ESCC. Conclusions. Over-expression of CD44v6 can be an indicator of the malignant potential of ESCC.