Here's why:

* Uncontrolled Cell Growth: Cancer arises when cells in the body begin to grow and divide abnormally, without the usual checks and balances that regulate normal cell growth.

* Loss of Control: The cells lose the ability to respond to signals that tell them to stop growing or to die when they are damaged or old.

* Formation of Tumors: This uncontrolled growth can lead to the formation of tumors, which are abnormal masses of tissue.

* Spread to Other Areas: Cancerous cells can also invade nearby tissues and spread to other parts of the body, a process called metastasis.

Important Note: While cancer is a general term for this disorder, it is a very broad category. There are many different types of cancer, each with its own specific characteristics and causes.