NPM1 and central nervous system cancer: NPM1 is overexpressed in several tumors, including prostate, liver, gastric, colon, pancreas, glioma and glioblastoma, astrocytoma and others.16 Its overexpression often correlates with mitotic index and metastatization and it was proposed as an adverse prognostic marker.17, 18 The NPM1 gene is also frequently altered in hematological malignancies arising from chromosomal translocations.