IDH1 and neoplasm: While extent of tumor resection and residual tumor volume has been shown to be significant prognostic factors for low grade gliomas5–7,37,38, IDH1/2-mutant and 1p/19q codeleted tumors are extremely sensitive to chemotherapy and radiation and it was reported that extent of resection was not prognostic for this type of tumor7,8, which oncological feature is less prominent in IDH1/2-mutant and 1p/19q non-codeleted gliomas5–7,38.