In line with studies from glioma and other non-cancerous CNS disorders [31, 32], flow cytometry analysis showed that only a small percentage of parenchymal microglia expressed MHCII or CD11c independent of the breast cancer model (range 3–30% and 2–6.5%, respectively; Figure 2D–2E, Supplementary Figure S4B, Supplementary Figure S5A–S5B). This evidence concerns the gene ITGAX and central nervous system cancer.