How do oncogenes contribute to the development of cancer?

Oncogenes are genes that, when mutated or expressed at high levels, have the potential to contribute to cancer development. They are primarily involved in promoting cell growth and division. When functioning normally, these genes play a crucial role in the regulation of cell proliferation, differentiation, and survival. However, mutations can lead to their activation, resulting in uncontrolled cell proliferation.

The transformation from a normal gene into an oncogene often occurs through point mutations, gene amplifications, or chromosomal translocations. Once activated, these oncogenes can lead to constant signaling for cell division, regardless of normal regulatory mechanisms. This unregulated growth is a hallmark of cancer, allowing cells to bypass mechanisms that typically control the cell cycle, leading to tumor formation and progression.

In contrast, genes that inhibit cell growth serve as tumor suppressors; they help prevent uncontrolled cell proliferation. Similarly, DNA repair mechanisms work to correct mutations and maintain genomic stability. Thus, while the other options highlight important cellular functions, they do not pertain to the direct role of oncogenes in promoting tumorigenesis.