Moreover, secretion of platelet factor 4 (PF4), a growth factor critical in GBM invasion [36], was reduced following vehicle treatment in Olfml3-/- microglia compared to isogenic control cells (426.0 ± 437 vs. 721.2 ± 206; p < 0.05) (Figure 5I). This evidence concerns the gene PF4 and glioblastoma.