What is Cancer?

What is Cancer?

Cancer cells are very similar to cells of the organism from which they originated and have similar (but not identical) DNA and RNA. This is the reason why they are not very often detected by the immune system, in particular if it is weakened. Cancer cells usually have an increased ability to divide rapidly and their number of divisions is not limited by telomeres on DNA (a counter system to limit number of divisions to 40-60). This can lead to the formation of large masses of tissue and in turn may lead to disruption of bodily functions due to destruction of organs or vital structures.