Tumor-associated macrophage infiltration in meningioma. Issue 1 (19th September 2019)

• Record Type: Journal Article
• Authors: Proctor, Dustin T; Huang, Jordan; Lama, Sanju; Albakr, Abdulrahman; Van Marle, Guido; Sutherland, Garnette R
• Is Part Of: Neuro-oncology advances. Volume 1:Issue 1(2019)
• Publication Date: 2019-09-19
• Subjects: macrophage -- meningioma -- microenvironment -- M1:M2 TAM ratio -- tumor recurrence; 616.99481
• DOI: 10.1093/noajnl/vdz018
• Languages: English
• ISSNs: 2632-2498

Abstract

Abstract: Background: Meningioma, a most common brain tumor, has a high rate of recurrence. Tumor-associated macrophages (TAMs) are the most abundant immune cell type in meningioma. TAMs display functional phenotypic diversity and may establish either an inflammatory and anti-tumoral or an immunosuppressive and pro-tumoral microenvironment. TAM subtypes present in meningioma and potential contribution to growth and recurrence is unknown. Methods: Immunofluorescence staining was used to quantify M1 and M2 TAM populations in tissues obtained from 30 meningioma patients. Associations between M1 and M2 cells, M1:M2 cell ratio to tumor characteristics, WHO grade, recurrence, size, location, peri-tumoral edema, and patient demographics such as age and sex were examined. Results: TAM cells accounted for ~18% of all cells in meningioma tissues. More than 80% of infiltrating TAMs were found to be of pro-tumoral M2 phenotype and correlated to tumor size ( P = .0409). M1:M2 cell ratio was significantly decreased in WHO grade II, compared to grade I tumors ( P = .009). Furthermore, a 2.3-fold difference in M1:M2 ratio between primary (0.14) and recurrent (0.06) tumors was observed ( n = 18 and 12 respectively, P = .044). Conclusion: This study is the first to confirm existence of pro-tumoral M2 TAMs in the meningioma microenvironment, emphasizing its potential role in tumor growth and recurrence.