ANALYSIS OF RELATIONSHIP BETWEEN EXPRESSION OF STEM CELL TUMOR MARKERS (ALDH-1 AND SOX-2) AND CLINICOPATHOLOGICAL CHARACTERISTICS OF MALIGNANT AND BENIGN SALIVARY GLANDS NEOPLASMS
Salivary glands; Neoplasms; Stem cells; Immunohistochemistry; Western blot.
Salivary gland tumors consist of a diverse group of lesions with complex clinicopathological characteristics and distinct biological behaviors. These tumors correspond to approximately 3% to 6% of neoplasms of the head and neck region. Surgery remains the most used therapeutic approach for patients with these neoplasms, leading to high morbidity and unsatisfactory results in many cases. The molecular mechanisms that are associated with a low response to radio-chemotherapeutic treatment in cases of salivary gland tumors remain unknown, however, it is important to note that stem cells within a tumor are considered resistant to chemotherapy and radiation due to, at least in part, to the decreased rates of proliferation and the differential function of the carrier proteins. In this regard, stem cell markers such as NANOG, OCTA-4, CD44, SOX-2, SOX-9 and ALDH-1 have been used to identify this population of cells in various human solid tumors. In view of the above, the objective of this study will be to evaluate and quantify the expression of markers related to stem cells (ALDH-1 and SOX-2) in salivary gland neoplasms and to verify if such expression is associated with clinicopathological data of the patients. Expression of the proteins will be obtained through immunohistochemical technique of biotin-free immunoperoxidase and quantified by the Western blot technique. We selected 100 cases of malignant neoplasms and 50 cases of benign salivary gland neoplasms to carry out the study. Clinicopathological data such as gender, age, anatomical location, clinical staging (TNM), treatment, presence of nodal or distant metastasis, and clinical outcome of the patients will be obtained through the medical records of the selected patients. Once the analyzes are performed, the data will be tabulated in Microsoft Excel® software (Microsoft Corporation, USA) and later transferred to a database created in SPSS ® software for Windows (Statistical Package for Social Sciences, IBM, USA), version 20.0. For all the statistical tests used, the level of significance will be set at 5% (p <0.05). The results of the present study may help elucidate the importance of tumor stem cells in the development and behavior of salivary gland tumors.