PTEN and astrocytoma (excluding glioblastoma): To date, chromosomal gains (+7) and losses (−10), allelic losses (10q, 9p), oncogene amplifications (MDM2, CDK4, EGF), and homozygous deletions and mutations of tumor suppressor genes (CDKN2A, TP53, PTEN, RB1, DMBT1) have been the most frequently found alterations in astrocytoma.