Astrocytomas demonstrated a significantly higher frequency of both CDKN2A heterozygous (16/47 cases, 34%) and homozygous deletion (8/47 cases, 17%) than other histological groups (p ≤ 0.0001 and p = 0.006, respectively). The gene discussed is CDKN2A; the disease is astrocytoma (excluding glioblastoma).