What are proto-oncogenes?

Proto-oncogenes are normal genes that play a crucial role in regulating cell growth and division. They produce proteins that are involved in signaling pathways that promote cell proliferation and survival. When these genes undergo mutations or are subjected to certain environmental factors, they can become oncogenes, which are genes that have the potential to cause cancer. The mutated form of the proto-oncogene leads to uncontrolled cell division and growth, contributing to tumor development.

The other options describe different types of genes with distinct functions. Genes that suppress tumor formation are known as tumor suppressor genes, which help control cell division and can prevent cells from becoming cancerous. Genes that initiate apoptosis are involved in programmed cell death, a process that eliminates damaged or unwanted cells. Finally, genes responsible for DNA repair help maintain genetic integrity by correcting errors that occur during DNA replication. Each of these roles is vital in the context of cellular regulation and cancer prevention, but only proto-oncogenes specifically relate to the promotion of growth that can lead to cancer when mutated.