Murine cells of origin for SHH-MB express high levels of the maintenance DNA methyltransferase DNMT1, and since expression of other DNA cytosine methyltransferases is virtually absent, we assume that consistent DNA hypomethylation effects across the genome of several SHH-MB tumor cell models are a direct consequence of the inhibition of DNMT1 function. This evidence concerns the gene DNMT1 and neoplasm.