What cancer actually is ?

I have listened a few people getting wrong about 'What cancer is' some say its organ failure some say its a disease(that's the worst one) and even a communicable disease. I wanna clear this and tell you what cancer really is. Cancer is a condition in which the body cells refuse to die and continue reproducing and utilizing the body's resources. let's explain this in a simple way suppose your body is a battle field and the immune system is the army which protects your body and keeps you alive and your body cells safe now suppose you body cells are the citizens now in in case of cancer the citizens(body cells) gets corrupted by some means such as radiation, tobacco, cigarette smoking etc. Now cells are usually supposed to commit suicide when they have done their work and stop reproducing but in the case of cancer the citizens (cells) refuse to die and keeps reproducing and using up the body resources now generally the army(immune system) has its own way to tackle this and kill those cells and keep you alive and prevent you from getting cancer but the cancer cells still keeps reproducing hiding from the immune system growing and growing until it is too late and your body lose the war and hence you die. The biggest problem in cancer prevention is that it develops inside our body with no interaction of any virus or bacteria and