Most Cancers Require at Least Two Mutations: 1) One in an Oncogene

Multiple Choice

Most cancers require at least two mutations: 1) one in an oncogene, which encodes proteins that trigger cell division, and 2) one in a tumor suppressor gene, whose protein products, in their unmutated form, play a key role in preventing the cell cycle from progressing if the DNA is damaged or in the absence of specific cues. Which class of proteins might be considered tumor suppressors?

A) Cdk inhibitors
B) cyclins
C) growth factor receptors
D) microtubules
E) transcription factors