What is the primary function of tumor suppressor genes?

Tumor suppressor genes play a crucial role in regulating cell growth and division, primarily functioning to inhibit these processes. They act as a safeguard against uncontrolled cell proliferation, which is a hallmark of cancer. By producing proteins that can either slow down the cell cycle or promote DNA repair, tumor suppressor genes help maintain normal cellular function and integrity.

When these genes are functioning properly, they can prevent the formation and growth of tumors by stopping cells from dividing too quickly or in an unregulated manner. Mutations or deletions in tumor suppressor genes can lead to a loss of function, ultimately resulting in unchecked cell growth and the development of tumors.

While the other options reflect important cellular processes related to cancer and immunity, they do not accurately describe the primary role of tumor suppressor genes. For instance, promoting cell division (the first option) is the opposite of what tumor suppressor genes do. Triggering apoptosis in cancer cells (the third option) is a mechanism that can involve other pathways and genes, but it is not the main function of tumor suppressor genes. Enhancing immune response (the fourth option) relates to immune system functions and is not directly tied to the role of tumor suppressor genes in regulating cell growth.