Teratoma: The monster that may lead to the cure?
The term "teratoma" originating from the Greek word teraton meaning monster, is used to describe a kind of tumor that forms from pluripotent germ cells. Pluripotent cells are unique in the way in which they demonstrate the ability to produce biological responses very similar to that of normal human tissue. Teratomata usually consist of a tumor that is very different compared to the issue of the area in which it is growing. What is most alarming and many times horrifying about teratomata is that it can grow hair and teeth very similar to real human tissue. These tumors have puzzled scientists, psychics, doctors and patients for centuries. Early beliefs blamed the individual suffering from the condition for swallowing hair or other body parts and that this growth was a punishment for cannibalism. Other beliefs include witchcraft and curses as well as a punishment for adultery with the devil. While it has not been proven, certain manuscripts state that due to their human-like characteristics, there was a time in which the Roman Catholic Church considered teratomata to be a forming embryo and required it to be baptized. The parthenogenic theory is now the one that is most widely accepted.
This kind of tumor is categorized into three phases: a mature teratoma (which is normally benign), immature (which is malignant) and monodermal or highly specialized teratoma. Some teratomata contain mature tissues such as hair follicles, fat tissue, sweat glands, partially or fully developed nerve tissue, and tissues strongly resembling human teeth. Teratomata usually form in the ovaries of women, testes of men and in the sacrum (large triangle-shaped bone found at the end of the spinal column) of children. The prognosis of a patient with a teratoma varies highly depending on the case and the location and growth of the tumor. Ironically, as gruesome as this condition may seem, these so called "monster tumors" may be the answer to one of the most controversial and contemporary ethical and scientific debates: stem cell research.
The very characteristics that make these tumors frighteningly freakish may be the most valuable to scientific research. The ability of teratomata to grow human cells without ever becoming a human embryo would eliminate the debate over the ethicality of human stem cell research. Since these tumors grow actual human tissue, they would be more effective in the laboratory than animals and would also allow researchers the freedom to experiment with material that is not alive.
Karl Skorecki, one of the world's leading researchers exploring this method, has expressed his frustration at the limitation of having to work with animals as test subjects: "Drugs that work well in mice don't always pan out in humans, because with mice, you have a microenvironment with no human cells". In order to test the expediency of this theory Mr. Skorecki and his colleagues injected human teratomatic tissue into the leg of mice and then injected cancerous cells into the benign tumor. As expected, the cancerous cells spread quickly and provided an ideal environment for testing cancer-fighting medications. Teratomata have the ability to grow many different kinds of human tissue and will allow tests to be run on a large variety of different tissues. The great advantage of this discovery is that since the teratomata's characteristics are almost identical to that of human tissue, the reaction to the medication being tested will very likely be the same. If this project is successful, anticancer agents will be tested on living "human" tissue without having to use any human subjects. It is likely that this new this new method of testing drugs could substitute early stage human trials.
The reason for which these tumors are so closely similar to human tissue is that they appear when egg cells develop as if they had been fertilized and continue to divide and multiply just as a human embryo does in the first stages of development. More importantly, these tumors can produce stem cells that are able to develop into hundreds of tissue types, allowing testing to be preformed on different kinds of tissue. This material has the potential to be used in research for treating disease like Alzheimer's, however; because there is very little control on the part of the researcher in determining what kind of tissue the tumor will produce, researchers may end up with random tissues ranging for sweat glands to hair follicles. Dr. William Hurlbut, a biologist and ethicist of Stanford University describes this as "jumbled puzzle parts". Dr. Hurlbut believes that instead of taking stem cells from embryos, researchers should take the tissue from teratomata - thereby conducting stem cell research without the moral implications.
This new discovery is still at its early stages and many tests and trials are going to be needed in order to establish the teratoma as a potential testing ground for new anticancer drugs. Interestingly enough, the macabre biological phenomenon that is the teratoma could possibly hold the answers that we have been looking for.
1. Wikipedia Teratoma page: http://en.wikipedia.org/wiki/Teratoma
2. eMedicine: http://www.emedicine.com/med/topic2248.htm
3. The New York Times- "Monster Tumors show scientific potential in war against cancer":http://www.nytimes.com/2006/06/06/health/06tera.html?ex=1159934400&en=abb7c40756a9cbfe&ei=5070