Clinicopathological significance of expression of CD44 variants in head and neck squamous cell carcinoma

Splice variants of the cell surface glycoprotein CD44 have been reported to he associated with the progression of various human tumors. The aim of thi s study is to determine the correlation between the expression of CD44 isof orms, especially CD44 variant 2 (CD44v2), and the clinicopathological featu res of head and neck squamous cell carcinomas (HNSCCs). The expression of C D44 isoforms was evaluated immunohistochemically in paraffin-embedded tissu es from 89 primary lesions, using monoclonal antibodies against CD44 standa rd (CD44st), CD44 variant 6 (CD44v6) and CD44v2, Cancer tissues from 89 (10 0%), 85 (95.5%) and 59 (66.3%) patients showed positive immunoreactivity fo r CD44st, CD44v6 and CD44v2, respectively. A significant correlation was ob served between the down-regulation of CD44v2 and poorer differentiation of the tumor cells (P=0.02). We could not find any significant correlation bet ween the expression of CD44v2 and T stage or N stage (Lymph node status). H owever, the rate of positive cervical lymph node metastasis tended to incre ase with reduced expression of CD44v2 (P=0.98). Down-regulation of CD44v2 e xpression was correlated with shorter overall survival (P=0.01). Furthermor e, Cox's multivariate analysis revealed that only CD44v2 expression and lym ph node status were independent prognostic factors. These findings suggest that down-regulation of CD44v2 expression mag be one of the biological mark ers for the degree of malignancy in HNSCCs.