Infiltration Characteristics Of TAMs And Correlation Between Tams Infiltration And Clinicopathological Factors In Buccal Mucosal Carcinoma

Purpose: Explore the infiltration characteristics of tumour-associated macrophages(TAMs)in buccal mucosal carcinoma and its correlation with the clinicopathological factors including PD-L1 expression,EGFR expression,and CD8+ T cells.Materials and methods: We retrospectively collected the clinical and pathological data of 613 patients with mucosal cancer after radical resection from January 2013 to December 2018.According to the criteria for inclusion and exclusion,46 patients with buccal mucosal cancer were screened.The expression of TAMs-related markers(CD68,CD163,CD206)and important components of the tumor microenvironment(CD8,PD-L1,EGFR)in surgical specimens was detected by immunohistochemistry in the tumor area,paratumor region and normal tissue region.The immunohistochemistry results were independently read by two pathologists in order to observe the infiltration characteristics of each index in different areas.A chi-square test was used to analyse the correlation between tumour-associated macrophages and clinicopathological factors,PD-L1 expression,EGFR expression and CD8+ T cell infiltration in patients with buccal mucosal carcinoma.Results: The mean values of CD68+ macrophages,CD163+macrophages and CD206+ macrophages in the tumour area were166.7±33.1/high power field,45.5±15.3/ high power field and 44.8±17.2/high power field respectively.TAMs infiltration was significantly higher in the tumour area as compared to the paraneoplastic area,whereas there was almost no TAMs infiltration in the normal tissue area.The analysis of the correlation between tumour-associated macrophages and clinicopathological features suggested that there was gender-related infiltration of CD68+ TAMs,which was more likely to be in the CD68+macrophage high expression group in female patients(P=0.036).The CD163+ TAMs high expression group was more commonly seen in T3-T4(P=0.006),N+(P=0.014),and stage III-IV(P<0.001).The group with high expression of CD206+ TAMs was more common in T3-T4(P=0.004),N+(P=0.009),and stage III-IV(P=0.001)patients.The correlation between TAMs and PDL-1 expression suggests that CD68+macrophage infiltration is positively correlated with PDL-1 IPS(P=0.017)and CPS(P=0.027).CD163+TAMs infiltration was positively correlated with PD-L1 TPS(P=0.002),IPS(P=0.018),and CPS(P=0.009).CD206+TAMs infiltration was positively correlated with PD-L1 TPS(P=0.035),IPS(P=0.029),and CPS(P=0.012).TAMs correlated with EGFR expression suggesting that CD206+ TAMs infiltration was more abundant in the EGFR high expression group compared to the low expression group(P=0.040).Conclusion: Tumour associated macrophages infiltrated mainly in the tumour mesenchymal area,while infiltration in the paraneoplastic area was significantly decreased,without significant infiltration in the normal tissue area.The high expression of M2 type TAMs was more commonly seen in patients with T3-T4,lymph node metastasis,and stage III-IV.The degree of TAMs infiltration was positively correlated with PD-L1 expression.CD206+ TAMs infiltration was positively correlated with EGFR expression(p= 0.040).