Using the MCP counter algorithm, we explored the relative content of eight immune and stromal cell types in the clusters that were previously identified (Figure 1A,B) We observed that GBM tumors with high levels of phospho-ERK1/2 were significantly enriched in cells of the monocytic lineage (P=0.045, Kruskal–Wallis) (Figure 2A). The gene discussed is MAPK3; the disease is glioblastoma.