<h4>Introduction</h4>Salivary gland tumors (SGTs) are uncommon lesions that account for 3 to 6% of head and neck cancers.<h4>Objective</h4>To investigate mismatch repair (MMR) proteins, tumor-infiltrating lymphocytes (TILs), and CD45RO expression in salivary gland tumors (SGTs).<h4>Methods</h4>Proteins MLH1, MSH2, MSH6, and PMS2 of the MMR proteins family and CD45RO were evaluated using immunohistochemistry (IHC). The gene discussed is MLH1; the disease is neoplasm.