THE ROLE OF TUMOR-ASSOCIATED MACROPHAGES IN THE PATHOGENESIS OF ORAL SQUAMOUS CELL CARCINOMA CORRELATED WITH THE CLINICOPATHOLOGICAL PARAMETERS

Abstract

Introduction: Oral cancer is a major health problem, causing high morbidity and mortality rates. Oral squamous cell carcinoma (OSCC) accounts for 90-95% of all oral malignancies. During the last decade, significant evidence has suggested that inflammatory tumor microenvironment (TME) plays an important role in tumorigenesis. The inflammatory cells and their signals are indispensable participants in the neoplastic process, fostering proliferation, survival, and migration of cancer cells. The macrophages are the most abundant and important stromal cells in the TME, which orchestrate the inflammatory response. They control the cellular proliferation and survival by stimulating the immune cells and by promoting integrated processes of inflammation and tissue repair. Therefore, the tumor associated macrophages (TAMs) may be of great prognostic significance in different types of tumors. Objectives: This study was conducted to assess the TAMs density in OSCC using CD163 in metastasizing and non-metastasizing OSCC. Moreover, the correlation of TAM density with the lymph node status and the different histopathological grades of OSCC was assessed. Materials and methods: The density of TAM was calculated in 30 surgical specimens taken from OSCC patients. Biopsies were taken from the primary tumor of 15 cases with lymph node metastasis and 15 cases with no lymph node metastasis. Fifteen normal mucosal tissues were taken from healthy individuals indicated for alveoloplasty as a control group. Immunohistochemical staining using the CD163 antibody was performed, using Labeled Strept-Avidin Biotin complex method. Positive cells were counted using the Image J free software package. Results:CD163 was expressed in human OSCC and the TAMs count was significantly correlated with lymph node metastasis and with the tumor differentiation. Higher density was detected in metastatic tumors and in the poorly differentiated OSCC than in the well and moderately differentiated cases. Conclusions: CD163 positive TAMs could be a prognostic factor in OSCC cases as TAM density was significantly correlated with the lymph node status and the grade of differentiation of OSCC.