IBA1, TMEM119, and CD206 in Glioblastoma: an Immunohistochemical Study exploring associations with Radiological Tumour Growth and Overall Survival

Purpose Tumour-associated macrophages and microglia (TAMs) are important components of the glioblastoma microenvironment. These cells may play a central role in tumourigenesis and progression, making them potential targets for novel therapies. In the present study we aimed to investigate if selected putative TAM markers are related to radiological speed of growth and overall survival. Methods The radiological speed of growth was retrospectively estimated in 88 glioblastoma patients, classified into faster- and slower-growing groups based on a Gompertzian growth model. Tumour samples underwent immunohistochemical analyses with the putative TAM markers IBA1 (pan-macrophage marker), TMEM119 (microglia marker) and CD206 (perivascular and recruited macrophages) to investigate their associations with tumour growth and overall survival. The immunoreactivity was digitally assessed using QuPath. Associations between the markers, radiological growth and corticosteroids were assessed using Mann-Whitney U-test. Impact on overall survival was investigated using univariable Cox regression. Correlations between the markers were assessed using Spearman’s rank correlation test. Results We found no significant association between the investigated markers and radiological growth rate or overall survival. The immunoreactivity of IBA1 and TMEM119 were significantly correlated and there were significantly higher expressions of IBA1 and CD206 in the patient group treated with corticosteroids. Conclusion We found no clear evidence that the immunohistochemical expression of these putative TAM markers influences radiological growth speed or overall survival in our retrospectively investigated glioblastoma patients.