Some studies suggest that the yield of such testing would be very low in grade 2IDH-mutant astrocytomas and therefore, it may be omitted (23,24) while CAP recommendations state “CDKN2A/Bhomozygous deletion testing should be performed on allIDH-mutant astrocytomas”(31). The gene discussed is CDKN2A; the disease is astrocytoma (excluding glioblastoma).