ALK and astrocytoma (excluding glioblastoma): Although IDH1 alterations were significantly associated with favorable OS and PFS for all grades of astrocytomas (S5 Fig and S1 and S2 Tables), ALK (5A4) status did not affect the prognostic significance of IDH1 gene alterations when the patients were subdivided into four groups on the basis of ALK (5A4) and IDH1 statuses (Fig 1D), in line with our previous study [25].