Ichimura et al. (44) reported that patients with astrocytoma with total 1p loss had a significantly better prognosis than those with other types of 1p status, and Otani et al. (45) found that patients IDH-mutated astrocytoma with 19q loss also had longer survival times than those with 19q intact astrocytoma, suggesting that single 1p or 19q loss may increase the clinical similarity of the tumor with the 1p/19q co-deleted tumor. Here, IDH1 is linked to astrocytoma (excluding glioblastoma).