The disorder in which cells lose the ability to control their growth rate is cancer.

Here's a breakdown:

* Normal cells have a tightly regulated growth cycle. They grow, divide, and die in an orderly fashion, ensuring the body functions properly.

* Cancer cells have escaped these controls. They grow and divide uncontrollably, forming a mass of abnormal cells called a tumor.

* This uncontrolled growth can invade surrounding tissues and spread to other parts of the body (metastasis).

There are many different types of cancer, each with its own unique characteristics and causes. However, the underlying mechanism of uncontrolled cell growth is common to all cancers.