Analysis of mouse medulloblastoma and precursor-cell methylation demonstrated a somatic origin for many alterations.

Analysis of germline DNA revealed two of these alterations to be of somatic origin.

Reprogramming events include both transcriptional silencing and activation of genes residing on chromosomes of somatic origin.

Tumor heterogeneity or neometaplasia may account for the origin of a tumor of germ cell type from a carcinoma of somatic origin.