What is the role of a tumor suppressor gene?

Tumor suppressor genes play a critical role in regulating cell growth and ensuring that cells divide in a controlled manner. Their primary function is to inhibit cell division, preventing excessive cell proliferation that can lead to tumor development. When these genes are functioning properly, they help maintain normal cellular processes, repair DNA, and initiate apoptosis (programmed cell death) if necessary.

If tumor suppressor genes are mutated or dysfunctional, their ability to inhibit cell division is compromised, which can lead to the uncontrolled growth characteristic of cancer. The significance of these genes makes them essential participants in the cellular mechanisms that protect against cancer formation.

The other options involve promoting growth or supporting cancer progression, which are not functions of tumor suppressor genes. They are designed specifically to maintain checks and balances on cell proliferation, distinguishing them from genes that would encourage or facilitate uncontrolled growth.