DNA Damage and Mutation
DNA damage can result from both internal (endogenous) and external (exogenous) sources. Each type of damage requires a specific repair mechanism, highlighting the importance of a diverse and efficient DNA repair system. When these repair processes are compromised, DNA lesions and mutations accumulate, potentially leading to the transformation of normal cells into cancerous ones. A reduced capacity for DNA repair has been associated with an increased risk of cancer, often linked to what are known as "low-penetrance genes." In cancer cells, the genome may exhibit various classes of mutations, many of which occur during the lineage of cells that already show early signs of abnormal or neoplastic transformation.