DNA plays several roles in the development of cancer. Changes in DNA can cause cancer by disrupting the way a cell grows and spreads. These changes often happen in genes, as they are specific segments of DNA containing instructions for making proteins or RNA molecules. Mutations in critical genes can cause cells to lose their ability to follow instructions correctly. As a result, these cells can begin to multiply uncontrollably. They fail to repair themselves properly and don't undergo programmed cell death when necessary. This unregulated cell growth and survival can ultimately lead to the development of cancer. Individuals with inherent chromosomal abnormalities are more prone to specific cancers, implying that alterations in the number of chromosomes may facilitate the progression of cancer.
Mutations can occur in specific genes that promote cell growth (oncogenes) or inhibit it (tumor suppressor genes). Additionally, if a DNA repair gene itself is damaged, the cell's ability to fix DNA damage is affected. As a result, errors can accumulate in other genes over time, increasing the risk of cancer formation. Lastly, self-destructive genes regulate apoptosis. If these self-destruction genes are damaged, faulty cells may survive instead of undergoing apoptosis, contributing to the development of cancer.