We determined the expression of the genes GPNMB and SPP1 in CD11b+ and CD11b- cells isolated from human GBM (CD11b+ n = 15, CD11b- n = 9), meningioma (CD11b+ n = 5, CD11b- n = 3), grade III anaplastic astrocytoma (CD11b+ n = 2, CD11b- n = 2), control brain (CD11b+ n = 5, CD11b- n = 2) and blood monocyte samples (n = 2). The expression of GPNMB and SPP1 was significantly higher in CD11b+ cells isolated from GBMs compared to CD11b+ cells isolated from control brain, benign meningioma samples, blood monocytes, and CD11b- cells in GBM. Bar graphs illustrate the absolute number of transcripts normalized to 100,000 transcripts of ACTB. Analysis was done by students t test. Error bars indicate the SEM. *, p<0.05; **, p<0.01; ***, p<0.001