Purpose: Adenoid cystic carcinoma (ACC) is one of the most common malignant salivary gland tumors. It is characterized by a high rate of recurrence, perineural invasion and development of distant metastases many years after removal of the primary tumor. Disorders of the induction of apoptosis and its cascade reactions where caspases are involved may be significant in the pathogenesis of this tumor. Methods: The immunohistochemical expression of caspase 9 and caspase 3 was analyzed by tissue microarray (TMA) in 50 cases of ACC in relation with different clinicopathological parameters (gender, age, localization, histological type and overall survival). Results: Caspase 9 was expressed in the cytoplasm and nuclei of ACC tumor cells with varying degrees of staining intensity (1+, 6%; 2+, 54%, 3+, 40%). Comparison of caspase 9 expression in tumor cells with clinicopathological parameters (gender, age, localization, histological type and overall survival) showed no statistically significant difference except that the expression was more pronounced in females. Caspase 3 was expressed in the cytoplasm of tumor cells with varying degrees of staining intensity (1+, 22%; 2+, 36%; 3+, 42%). No correlation between the expression of caspase 3 and clinicopathological parameters was noticed. Conclusions: The expression of caspases 9 and 3 in ACC of the salivary glands can contribute in the better characterization of molecules involved in apoptosis of tumor cells
