Intriguing stem cell paradoxes: from Pepsi to Pluripotency


I love paradoxes.

The great artist M.C. Escher was famous for his paradoxical drawings such as the one above.

Paradoxes make people think in a whole new way about something they thought they understood.

The stem cell field is full of paradoxes.

Below I list my favorite ones.

  • Most stem cell therapies will not transplant stem cells. Most “stem cell” therapies will not be transplants of actual stem cells, but rather almost always use differentiated cells made from stem cells.
  • Pluripotent stem cells are more similar to cancer cells than any other type of cell. The pluripotent stem cell field had its beginnings with studies of teratocarcinoma cancer cells, which are remarkably similar to “normal” pluripotent stem cells.
  • The developers of the first stem cell therapy did not know it involved stem cells. Bone marrow transplantation was not known to be a stem cell-based therapy when it was being developed and first used.
  • Adult stem cell research does not always only use adult stem cells. Adult stem cell research often can involve stem cells from children under the age of 18.
  • The main assay that scientists use to measure “stemness” is a tumor assay. The teratoma assay is used to measure stem cell pluripotency by most labs, but it was for many years first used as a tumorigenesis assay.
  • The same person who might ask in concern if their Pepsi has stem cells in it, will not ask if the “stem cell” treatment being injected into their vein has stem cells in it. An urban legend spread by opponents of embryonic stem cell research is that Pepsi has embryonic or fetal stem cells in it, but the same person might go get a “stem cell” transplant and never even ask if the transplant has stem cells in it and from what we know in many cases the treatment probably doesn’t have living stem cells in it.

Sometimes truth is stranger than fiction.

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