Teratomas: Terrible, but Maybe Also Terrific

I just wrote a piece about stem cells, and I'd like to take a moment to talk about one of the things I briefly mention in the article: teratomas, which, like most of the best things in medicine, are both intellectually fascinating and spectacularly gross. (For the sake of the squeamish, I'm not including any pictures except the one at left [apparently her name is "Tabitha"], but there is a disgusting one here.)

Teratomas are essentially tumors made of cells that have decided to differentiate into any old thing -- teeth, hair, fat. That goes a long way toward explaining their name, which comes from the root word for "monster" (as those of you who participated in our coin-a-new-word contest will know). Normally they tend to arise in the ovaries, testes, and sacra -- but in experiments, they also seem to turn up where scientists implant embryonic stem cells. You may know them from season 2 of Grey's Anatomy, in which a man thinks he is pregnant a la Arnold Schwarzenegger but turns out to be carrying a large teratoma instead. But what interests me most about them (at present, anyway) is their relationship with the aforementioned stem cells. Yes, they present a problem for embryonic research. But they might end up providing a solution to that very same problem:

As clusters of human cells that are not independent organisms, teratomas may prove better test subjects for drugs than lab animals, and they are inspiring ways to grow stem cells without harvesting embryos. ... Teratomas' most fascinating quality, Dr. Skorecki said, is their capacity to generate a smorgasbord of human tissue varieties, including bones, skin and ligaments. As a result, researchers testing a new medicine on a cancer-seeded teratoma can gauge what effects the drug will have on different cell types without enlisting human subjects. ... Like ordinary embryos, the tumors produce stem cells that have the potential to develop into hundreds of tissue types — raw material researchers may need to treat diseases like Alzheimer's.

PS: My husband says I've written the plural of teratoma incorrectly and that it should be "teratomata." Well, you say tera-tomata, I say tera-tomahta...