GPNMB and central nervous system cancer: In comparison to our naïve control brain tissue where the CD45−CD11b− represent macroglia and neurons, we detected a significantly lower percentage of GPNMB+ cells in non-immune cells of tumor-bearing mice, which predominantly represents the glioma cells (naïve brain = 16.59% ± 6.4 SD vs. tumor brain = 7.12% ± 4.17 SD; p = 0.0309) indicating that the glioma cells express less GPNMB than macroglia and neurons.