There was a post about a woman who grew a “homonculus tumor”, with brain tissue, teeth, a spinal nerves and other organs. But how? Human bodies can’t grow those things after birth, AFAIK. For example, once your adult teeth are in, that’s it. So how are tumors able to do this? Are the cells in tumors different from those found normally in human body?
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Doctor here
Only very specific, rare types of tumors grow hair and teeth and the like, theyre called “teratoma”
Basically, these types of tumors contain a special kind of stem cell called Germ Cells. Germ cells are also known as sperm cells in men, and egg cells in women. These germ cells start to grow human tissue like teeth cells, eyes, hair, like theyre developing a fetus.
Generally, these types of tumors are often found inside the reproductive system, in ovaries and testes
These kind of growths are called teratomas. The basic idea behind them is that at some point during your very early development, when you are still essentially just a tube of cells, some of these cells that would end up being programmed to do one sort of thing end up getting dislodged and moved to another part of that tube. So if you have a growth with teeth that is in your foot, that means that those cells were originally going to be jaw cells, already started started to differentiate into that, and then they ended up getting dislodged and moved.
Many tumors have mutations that reactivate Gene’s that are only active during embriogenesis. Your cells contain all the genetic information required to grow you from an embryo. These Gene’s are controlled ie. turned off, after their job is done (embryo – fetus). Cancer cells accumulate mutations due to their irregular growth, and chance can cause these embryonic Gene’s to become active again. This can rarely occur in stem cells that are not fully differentiated (locked into a specific tissue type), and this can lead to the growth of a variety of tissue types. There are even examples of cancer mutations reversing differentiated cells into a pluripotent form (they can turn into variety of tissues).
Just FYI, the teeth and nerves and stuff that teratomas grow are more or less absolutely trash and useless. Those structures that we need and it would be amazing to grow in a lab are extremely complex, and what grows out of a tumor is basically the building blocks of those structures thrown together randomly.
It would be like having a monkey mash the keyboard to write a movie. 99.99999999% of the time it would be absolutely meaningless nonsense.
Simple reason: Your body isn’t designed to regrow things from the stem cells it has. Those stem cells *can* do it (they’re not diversified and are capable of becoming any organ), but there’s no instruction available to make them do it.
A teratoma is effectively a cancer in a stem cell that causes it to start dividing and doing ‘stuff’ that it’s programmed to without proper instruction, let alone in a way that would produce a desired outcome.
It just starts mulitplying on its own and the damaged DNA is just telling itself to start dividing into whatever it can – although there is enough coordination to produce organs like eyeballs and teeth. But not in a way that makes sense (ie, it makes a clump of random eyeballs, hair, teeth instead of a skull with eye sockets, a mouth, jaw, etc.).
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