no-approval

Loss of one copy each of chromosome arms 1p and 19q, together with an IDH mutation, defines oligodendroglioma in the WHO 2021 classification. It predicts a slower course and a good response to chemotherapy, and separates oligodendroglioma from astrocytoma.

AR-V7 is a shortened androgen receptor that lacks the part hormone drugs bind, so it stays active without testosterone. Found in circulating tumour cells, it predicts poor response to abiraterone and enzalutamide, but no label uses it yet.

Class II and III BRAF mutations sit outside codon 600 and signal as pairs (class II) or by leaning on RAS (class III). Approved BRAF inhibitors do not work on them, and no drug is yet approved for them; pan-RAF inhibitors are in trials.

MET amplification means extra copies of the MET gene, either as a primary driver in a few lung cancers or as the escape route after EGFR inhibitors. No label yet selects on it; trials define it by FISH ratio or copy number.

Methylation of the MGMT promoter switches off the repair enzyme that undoes temozolomide's damage. Methylated glioblastomas live longer on temozolomide; unmethylated ones gain little, and trials now use the result to spare or intensify chemotherapy.

MYCN amplification, more than four times the normal copy number of the gene on FISH, marks the most aggressive fifth of neuroblastomas and puts a child in the high-risk group whatever their age or stage. No drug targets it; it decides how much treatment is given.