Increased Infiltration of M2-Polarized Tumour-Associated Macrophages is Highly Associated with Advanced Disease Stage and High Expression of PD-L1 in Buccal Mucosa Carcinoma

Abstract

Abstract Objective: To assess the infiltration characteristics of tumour-associated macrophages (TAMs) in buccal mucosa carcinoma (BMC) and the correlation of these features with clinicopathological factors. Materials and methods: Immunohistochemistry was used to detect the expression of TAM-related markers (CD68, CD163, CD206), CD8+ T cell markers, PD-L1, and epidermal growth factor receptor (EGFR) in 46 patients with mucosal cancer after radical surgery. In addition, the correlation between TAM infiltration and clinical characteristics, PD-L1 expression, and EGFR expression was analysed. Results: A high infiltration level of M2-polarized (CD206+) TAMs and M2c-polarized (CD163+) TAMs was more common in stage T3-T4, N+, III-IV patients than in other patient groups (P < 0.05). The infiltration degree of M2-polarized (CD68+) TAMs was positively correlated with the PD-L1 TPS (P = 0.0331). The infiltration level of M2-polarized (CD206+) TAMs was higher in the EGFR high expression group than in the EGFR low expression group (P = 0.040). Conclusion: High infiltration of M2-polarized TAMs is highly associated with advanced disease stage and higher expression of PD-L1 and EGFR in BMCs, suggesting that M2-polarized macrophage infiltration can serve as a potential therapeutic target.