An array of miRNAs, including miR‐155, miR‐183, and miR‐4476, has been reported as signature miRNAs in IDHmt glioma.[32, 46, 47] In this study, we report a novel IDHmt signature miRNA, miR‐19a, which is up‐regulated in a cellular setting in which IDH mutation or its metabolic product, D2HG, prevails. The gene discussed is IDH1; the disease is central nervous system cancer.