Cancer Is to Embryology as Mutation Is to Genetics: Hypothesis of the Cancer as Embryological Phenomenon

Figure 5

Differentiation and neoplasia. The normal cell lineage is at the bottom. Carcinogenesis may involve S, A, B, or C cells individually, giving origin to their corresponding malignant cell types. Their potentials for differentiation are indicated by the arrows. The cancers of endodermal and mesodermal origin are always the worst (thick arrow) in comparison with the ectodermal cancers (thin arrow) with a few exceptions as outlined in the article. EC: ectodermal origin; M: Mesodermal origin; and E: endodermal origin. Adapted from Pierce, 1983.