NUSAP1 and central nervous system cancer: Furthermore, NUSAP1 expression increased markedly with human glioma WHO grade and quantitative IHC analysis revealed that the mean optical density (MOD) of NUSAP1 staining in glioma cells increased significantly with the WHO grade, consistently (Fig. 2, C-E), suggesting that high NUSAP1 protein expression contributes to glioma progression.