Of Germ Cells, Trophoblasts, and Cancer Stem Cells

Abstract

The trophoblastic theory of cancer, proposed in the early 1900s by Dr John Beard, may not initially seem relevant to current cancer models and treatments. However, the underpinnings of this theory are remarkably similar to those of the cancer stem cell (CSC) theory. Beard noticed that a significant fraction of germ cells never reach their final destination as they migrate during embryonic development from the hindgut to the germinal ridge. In certain situations, upon aberrant stimulation, these vagrant germ cells are able to generate tumors. Simplistically, the CSC theory surmises that a small population of tumorigenic cells exists, which initiate and maintain tumors, and these cells have a likely origin in normal stem cells. Both these theories are based on the potential of a single primitive cell to form a tumor. This has a major implication for cancer therapy, in that only a small percentage of cells need to be targeted to ablate a tumor.