What characterizes oncogenes in relation to cancer?

Oncogenes are mutations of normal genes called proto-oncogenes, which play a critical role in normal cell growth and division. When proto-oncogenes become mutated or express at inappropriate levels, they can lead to abnormal cell behavior. This alteration results in the loss of regulatory control over cell proliferation and survival, allowing cells to divide uncontrollably. Consequently, oncogenes promote cancer by disrupting the normal checks and balances that regulate cell growth.

The other options do not accurately represent the role and function of oncogenes. While there are genes that can prevent cancer (tumor suppressor genes), oncogenes specifically facilitate processes that can lead to cancer development. Additionally, oncogenes do not exclusively cause mutations in non-cancerous cells, nor do they enhance the immune response to cancer cells. Their primary function is related to promoting uncontrolled cell division, a hallmark of cancer.