What is the difference between oncogenes and tumor suppressor genes?

Oncogenes and tumor suppressor genes play crucial roles in regulating cell growth and division, which is fundamental to understanding cancer biology. Oncogenes are mutated forms of normal genes, known as proto-oncogenes, that typically promote cell division and survival. When these genes are activated or overexpressed, they drive excessive cell proliferation and can lead to uncontrolled growth, which is a hallmark of cancer.

In contrast, tumor suppressor genes normally function to inhibit cell division, repair DNA errors, or promote apoptosis (programmed cell death) when necessary. The inactivation or mutation of these genes removes critical checks on the cell cycle, again facilitating uncontrolled growth.

Understanding this distinction is essential for comprehending how alterations in these gene types contribute to the development of cancer. The correct answer highlights the opposing roles that oncogenes and tumor suppressor genes play in cellular regulation, which is key to grasping their contributions to oncogenesis.