Fact 1: Cancer is a disease that occurs when the cell cycle is no longer regulated.

Fact 2: Another critical protein in regulating the cell cycle is the tumor suppressor protein p53 .

Given the two facts above, answer the question "One tumor suppressor protein which often results in cancer when it stops functioning is:" with the following options: 
- gene
 - p53
 - tumors
 - HIV
 - enzyme
 - tRNA
 - DNA
 - TRH


 

  p53       