In the human body, each normal cell "understands" that it is a part of something larger.

Normal cells serve that larger thing, and in return, the human body protects and feeds them. Cancer cells do nothing for their larger thing, spend their time constantly "partying", multiplying, and devouring their larger thing, and then wonder why their larger thing attacks them. A normal cell lives a prosperous life in service of its larger thing. A cancer cell has no future, because either its larger thing will kill it, or it will kill its larger thing and thus itself.