Expression and Interactions Between Cell Adhesion Molecules CD44v6 and E-Cadherin in Human Gliomas

Background. Gliomas are a heterogenous group of tumors that show the same histological features but differ in their behavior. Gliomas are characterized by biological aggressiveness and extensive infiltrative growth into surrounding healthy brain tissue. Objectives. In this study we estimated CD44v6 and E-cadherin expression and correlation between CD44v6 and E-cadherin in relation to glioma malignancy. We also analyzed simultaneous expression of CD44v6 and E-cadherin in the same tumor sample in order to determine the biological tumor behavior. Material and Methods. Expression of CD44v6 and E-cadherin was evaluated on ninety-two formalin-fixed paraffin-embedded glioma tissue blocks using immunohistochemistry (IHC). Results. CD44v6 expression was found in 71.6% of gliomas. There was a statistically significant difference between the frequency of positive cases for CD44v6 expression in low (grade I) vs. high (grade IV) as well as in grade I vs. grade II of glioma malignancy (p = 0.001). E-cadherin membrane staining was observed in 28.8% of gliomas. No significant differences were observed between E-cadherin expression and grade of gliomas (p > 0.05). However, re-expression of E-cadherin was found in grade II gliomas. In this group, E-cadherin expression was revealed in 43.3% of the cases. In order to define the relationship between CD44v6 expression and E-cadherin, we analyzed the simultaneous expression of CD44v6 and E-cadherin in the same glioma sample in the whole group and in respect to the degree of glioma malignancy. A positive correlation between studied biomarkers was observed in the analyzed gliomas (p = 0.004) but a simultaneous expression of CD44v6 and E-cadherin revealed no significant differences in respect to glioma malignancy. Conclusions. Our results showed that the level of E-cadherin might reflect different biological features of gliomas, whereas CD44v6 is associated with tumor cell malignancy. The simultaneous presence of CD44v6 and E-cadherin in a set of low-grade gliomas indicates that both these molecules might strengthen cell migration and may be a hallmark of glioma invasive growth.