Question about stem cells

[rakuenso]

Last time I checked, embryonic and adult stem cells were able to continuously divide independent of a telomerase enzyme. But also last time I checked uncontrolled cell growth is also one of the six immunities that cancerous cells have, what is it that allows them to continuously divide independently and not turn cancerous when injected into foreign tissues?

[Mokele]

Cancer cells, while immortal, also have other specific characteristics, mostly related to the control of the cell cycle (or lack thereof),

 

Most cells in a metazoan grow, then replicate their DNA, then grow some more, then divide. Getting to replicate the DNA, or even really do any of that (as opposed to just chilling out at the same size), is controlled both internally and externally. The relevant external controls have to do with, for instance, space; if there's not enough room, they don't divide. Cancer cells lack these controls, due to genetic damage, so they just divide as fast as they can, and grow as big as they can. Stem cells have these controls, so they don't divide uncontrolably.

 

However, telomerase-producing adult stem cells do already have one of the ways of becoming cancerous, which is why cancer occurs most often in tissues with such stem cells rapidly dividing, such and the bowel or epidermis.

 

Mokele