Leveraging the longitudinal attributes of our model, we observed that microglia cluster 2 gained expression of proinflammatory markers (Cxcl2, Cxcl3, Cxcl10, Il1b, Tnf, Ccl3), neutrophil chemotaxia (Cxcl10, Il1b, Ccl4, Ccl3, Cxcl3, Cxcl2, S100a9) and positive response to phagocytosis (Il1b, Gata2, Tnf) in early GBM when compared with normal brain (Fig. 6a and Extended Data Fig. 7a), suggesting that early GBMs activate an inflammatory response in microglia (2). This evidence concerns the gene S100A9 and glioblastoma.