IDH1 and diffuse astrocytoma: In one cohort of diffuse supratentorial low-grade gliomas, 1p19q co-deletion status was non-significant after adjusted multivariable analysis.29 In multivariable analysis, EFS was significantly inferior among those with diffuse astrocytoma histology,34,49 adjusted for IDH mutational status.46 IDH mutant status,29 1p19q co-deletion32,33 and O6-methylguanine-DNA methyl-transferase (MGMT) methylation33 were favorably associated with prolonged EFS when compared to IDH wild type gliomas.