Differentially expressed genes at one end of the microglia trajectory included genes that are characteristic of disease-associated microglia (DAM),23,24,25 such as Apoe, Trem2, Gpnmb, Csf1, Spp1, and Il1b. Using the DAM and mesenchymal gene expression signatures, we introduced a pseudotime in each of the two trajectories describing the transition of neuroepithelial-like tumor cells into mesenchymal-like tumor cells and homeostatic microglia into DAM, respectively (Figure 6A). Here, IL1B is linked to neoplasm.