METTL3 and malignant glioma: As a reversible epi-transcriptome modulator, methyltransferase-like 3 (METTL3) is a key member of the m6A methyltransferase complex, and has recently been reported to be essential for tumor progression in leukemia, hepatocellular carcinoma, and malignant glioma via diverse downstream genes [16, 17, 19].