Secreted levels of colony stimulating factor-1 (CSF-1), a cytokine critical for microglial recruitment and glioma growth [30], were reduced in Olfml3-/- microglia media compared to isogenic control media following exposure to vehicle (5.5 ± 0.3 vs. 33.8 ± 7, p < 0.01) and TGFβ treatment (β1: 12.6 ± 10 vs. 2.1 ± 0.3, p < 0.05; β2: 17.0 ± 4 vs. 3.2 ± 0.4, p < 0.01; β3: 11.4 ± 1 vs. 2.1 ± 0.4, p = 0.06) (Figure 4A). This evidence concerns the gene CSF1 and central nervous system cancer.