Assessment of the presence of interleukin 17+ macrophages and Th17 cells in situ in lip and oral tongue cancer

Abstract

Increasing clinical evidence indicates that Th17 cells may promote or inhibit tumor progression, however the exact role of these cells in Oral Squamous Cell Carcinoma (OSCCs) pathogenesis and progression remains unclear. Tumor associated macrophages are highly plastic phenotype cells which can differentiate as M1 or M2. The mechanism and cellular phenotype of IL-17 expressing macrophages are unknown. 40 cases of lip and 28 of tongue SCCs were submitted to immunohistochemical analysis, and histologically graded. In tongue cases TNM was analyzed. The number of IL-17⁺ T cells was higher in lip SCC (p = 0.028). IL-17⁺ macrophages was greater in tongue SCC (p = 0.014). There were more IL-17⁺ macrophages in the high-grade malignancy oral tongue SCCs (p = 0.016), yet there was no significant difference in the numbers of RORγt⁺ lymphocytes by histopathological or TNM analysis. This study provides evidence concerning IL-17's pleiotropic roles, being possibly dependent on its cellular sources in the tumor microenvironment.

Keywords: Interleukins; Lymphocytes; Macrophages; Oral squamous cell carcinoma; Tumor microenvironment.