EXPRESSION OF CD105 AND CD31 IN BENIGN AND MALIGNANT SALIVARY GLAND TUMORS WITH MYOEPITHELIAL DIFFERENTIATION (A COMPARATIVE STUDY).

Background and Aim: One of the strongest prognostic factors in tumor grading is tumor neovasculature. Hence, angiogenesis is an important target to eliminate tumor growth and metastasis. This study was carried out with the aim of evaluating the angiogenesis in salivary gland tumors by assessing microvessel density (MVD) using CD105 and CD31. This work also compared and correlated the expressions of both markers in benign and malignant salivary gland tumors (SGTs) and in grades of malignant tumors with myoepithelial differentiation. Material and Methods: The material of this work consisted of 76 paraffin embedded specimens including 20 benign tumors and 48 malignant tumors with different grades and types and 8 non neoplastic salivary gland tissues. Immunohistochemical staining was performed using both primary mouse monoclonal CD31 and CD105 antibodies for assessment of angiogenesis. Results: All studied cases showed positive CD31 and CD105 immunoreactivity. The study revealed a highly significant increase of CD31-MVD and CD105-MVD in malignant SGTs compared to benign tumors. Also, high grade malignancy demonstrated an increase in MVD when compared to low grade malignancy. In addition, malignant SGTs without myoepithelial cell differentiation showed significantly higher values of CD31-MVD and non significant difference of CD105-MVD compared to those containing myoepithelial cells. CD31-MVD values were always higher than CD105 in all studied cases. Conclusion: CD105 was more accurate in the assessment of tumor angiogenesis compared to the most commonly used CD31 panendothelial marker