IDH1 and astrocytoma (excluding glioblastoma): Satomi et al., using a combination of FISH and MLPA (multiplex ligation-dependent probe amplification), found a negative correlation between CDKN2A HD and OS in IDH-mutant grade 3 astrocytomas (n = 4/35 patients had a CDKN2A HD) (p < 0.001) but not in IDH-mutant high-grade gliomas (n = 13/27 had a CDKN2A HD) (p = 0.128).