Hashime said:
What happens when DNA is deformed?
It may cause desease/a useles cell.
It causes other enzymes to be formed, being either useless, or harmful.
It is also important where the DNA is deformed, because it can cause 1 enzyme to be different, or even dozens. which can be harmful.
That's how cancer starts.If in a cell a piece of DNA deforms in the growth section, it sometimes starts to multiply uncontrollably.Normal cells have this sort of buffer that tells them when and how to grow, cancer cells do no. if the mutantcells cannot be "peerpressured" by other cells anymore,(IE slightly controlled) it stops being beneign (or how that's spelled)and then it spreads throughout the body through the veins, and where-ever it lands it grows again. Causing small tumors to grow. leading ,eventually, to death.
Cancer is really hard to stop because the body thinks the cancercells are normal cells. And often it's recognised too late
TL;DR can cause cancer/other deseases/harmfull cells/useless cells
Source: my Biology book

(in Dutch, so don't bother looking it up XD)
[sub]Caption thinghy.. what is "teekag" ?[/sub]