What is the effect of mutations in tumor suppressor genes?

Mutations in tumor suppressor genes can lead to uncontrolled cell proliferation because these genes typically function to inhibit cell division, repair DNA, and trigger apoptosis (programmed cell death). When mutations occur in these genes, their ability to perform these critical regulatory functions is impaired. As a result, the cell can start to divide uncontrollably, contributing to the development and progression of cancer.

These mutations disrupt the normal checkpoints in the cell cycle, allowing cells to continue proliferating even when they are damaged or have accumulated mutations that would otherwise signal for repair or death. This is a significant mechanism in tumorigenesis, as it removes the key barriers that would normally prevent excessive cell growth.

In contrast to this, the other options present incorrect information about the role of tumor suppressor genes. Those that suggest regulated cell division, enhancement of tumor suppression, or that mutations are always beneficial do not accurately reflect the consequences of gene mutations that hinder the protective functions of tumor suppressors.