METTL8 and neoplasm: To determine the role of METTL8 in GSC biology, we employed a variety of well-established in vitro and in vivo assays, including the tumorsphere assay (a readout for GSC proliferation/self-renewal); soft agar colony formation assay (a readout for GSC clonogenicity and transforming potential); extreme limiting dilution assay (a readout for tumor-initiating cell frequency); Transwell migration and invasion assay; and xenotransplantation assay [7, 28].