Although additional investigation is needed to determine whether TET1 is a bona fide oncoprotein in MB tumorigenesis and whether overexpressed TET2 is cooperative with TET1 to establish global 5hmC level during MB tumorigenesis, our genetic studies demonstrate that TET1 modulates MB tumorigenesis by tumor-specific 5hmC formation along with NANOG. The gene discussed is TET1; the disease is neoplasm.