IMMUNOHISTOCHEMICAL ANALYSIS OF CHEMORESISTANCE-RELATED FACTORS IN SALIVARY GLAND NEOPLASMS
ABC transporters. Epithelial-Mesenchymal Transition. Multidrug resistance. Neoplasms of the salivary glands. Immunohistochemistry.
Multidrug resistance (MDR) in cancer is a complex and multifactorial process, in which tumors are intrinsically resistant to chemotherapy or acquire drug resistance over the course of treatment. Among the various mechanisms that may be associated with MDR, the increase in drug efflux and the epithelial-mesenchymal transition (EMT) process is highlighted. In this context, it is of fundamental importance the role of ABC transporters (ATP-binding cassette), a large family of ATP-dependent transmembrane proteins, such as ABCB1 and ABCG2, and transcription factors involved in TEM, such as Twist1 and Snail1. The transporters can be physiologically expressed in a variety of tissues. Their overexpression has been described and correlated with chemoresistance in several types of cancer, such as breast, prostate, and ovarian, among others. The connection between chemoresistance and EMT is still not well understood. Several mechanisms have been reported in this process, among them the association of transcription factors with ABC transporters. Regarding salivary gland neoplasms, the reasons why these tumors are inherently chemoresistant remain unclear. There are few studies in the literature evaluating ABC transporters and EMT with MDR and prognostic factors in salivary gland neoplasms. Thus, the present study aims to evaluate the immunohistochemical expression of ABCB1, ABCG2, Twist1, and Snail1 in malignant salivary gland tumors (mucoepidermoid carcinoma, adenoid cystic carcinoma, and acinar cell carcinoma), comparing with the expression in a benign tumor of the salivary gland (pleomorphic adenoma), in addition to correlating them with clinical-pathological and prognostic parameters. It is intended, therefore, to contribute with information that may improve the understanding of the role of ABC transporters and EMT in the MDR of these tumors.