WHO 2021

Question 1

1. differences in 2016 and 2021 histology

Answer 1

2016: oligodendroglioma vs oligoastrocytoma vs astrocytoma
2021: oligodendroglioma vs astrocytoma

Question 2

2. differences in 2016 and 2021 IDH status

Answer 2

2016 and 2021: IDH-mutant (+) vs IDH wildtype (-)

however glioblastomas in 2021 HAVE to be IDH-wildtype

Question 3

3. differences in 2016 and 2021 histologic grade

Answer 3

2016: for IDH-mutants broken into WHO II/III vs WHO IV (Glioblastoma, IDH mutant)
2016: for IDH-wildtype broken into WHO II/III (diffuse astrocytoma, IDH-wildtype) vs WHO IV (glioblastoma, IDH-wildtype
2021: for IDH-mutants broken into WHO 2 / 3 vs WHO 4 (astrocytoma, IDH mutant, WHO grade 4)
2021: for IDH-wildtype broken into WHO 2 /3 (molecular profile needed to determine further) vs WHO IV (glioblastoma, IDH-wildtype)

Question 4

4. WHO difference in 2016 and 2021 molecular profile

Answer 4

2016 molecular profile: splits the IDH-mutant WHO II/III based on 1p/19q codeletions, codeleted= oligodendrogliomas vs non-codeleted= diffuse astrocytoma, IDH-mutant
2021 molecular profile: splits the IDH-mutant WHO II/III based on 1p/19q codeletions, codeleted= oligodendrogliomas, vs non-codeleted ATRX loss TP53 mutation gets split based on CDKN2A/B non-deleted (astrocytoma, IDH-mutant, WHO grade 2 or 3) vs CDKN2A/B deleted which is considered an astrocytoma, IDH-mutant, WHO grade 4
For IDH-wildtype WHO 2 /3 cancers slit into diffuse astrocytoma IDH-wildtype vs if has gain of chr 7/loss of Chr 10 EGFR amplification TERT promoter mutation is a glioblastoma, IDH-wildtype