DNA repair

Definition

DNA repair refers to the set of processes by which a cell identifies and corrects damage to its DNA molecules. This is crucial because DNA can be damaged by various factors, such as environmental stressors, radiation, and errors during DNA replication. Effective DNA repair mechanisms are essential for maintaining genomic stability, preventing mutations, and reducing the risk of cancer, particularly since compromised repair systems can lead to uncontrolled cell growth and tumor formation.

5 Must Know Facts For Your Next Test

1. DNA repair mechanisms include several pathways, such as base excision repair, nucleotide excision repair, and double-strand break repair, each addressing specific types of DNA damage.
2. When DNA repair systems fail or are overwhelmed by damage, cells may undergo mutations that can lead to cancer development through the accumulation of oncogenic alterations.
3. Cells with defective DNA repair mechanisms often display genomic instability, which is a hallmark of many cancer types and contributes to tumor heterogeneity.
4. Certain inherited disorders, like xeroderma pigmentosum and Lynch syndrome, are caused by mutations in genes responsible for DNA repair, significantly increasing the risk of developing cancers.
5. Understanding DNA repair pathways is essential for developing targeted therapies in cancer treatment, as many current treatments aim to exploit the deficiencies in these pathways in cancer cells.

Review Questions

• How do DNA repair mechanisms contribute to genomic stability and the prevention of cancer?
  • DNA repair mechanisms are critical for maintaining genomic stability by correcting various types of DNA damage that occur naturally or due to external factors. When these processes function properly, they prevent the accumulation of mutations that could lead to uncontrolled cell division and tumor formation. If these repair systems are compromised or fail to respond effectively to damage, it can result in increased mutation rates and a higher likelihood of developing cancer.
• Discuss the implications of defective DNA repair systems in relation to inherited cancer syndromes.
  • Defective DNA repair systems play a significant role in inherited cancer syndromes, such as xeroderma pigmentosum and Lynch syndrome. Individuals with these disorders have mutations in genes responsible for specific DNA repair pathways. As a result, their cells are unable to effectively fix DNA damage, leading to an increased risk of developing various cancers at an early age. This connection highlights the importance of understanding DNA repair mechanisms in the context of hereditary cancer risk.
• Evaluate how knowledge of DNA repair pathways can inform therapeutic strategies for treating cancer.
  • Knowledge of DNA repair pathways is crucial for developing targeted therapies that exploit specific weaknesses in cancer cells. For instance, some treatments aim to inhibit certain DNA repair mechanisms in tumor cells that already have compromised systems. By doing this, therapy can increase the effectiveness of treatments like chemotherapy or radiation therapy by preventing cancer cells from repairing the damage caused by these agents. Understanding these pathways allows researchers to create more personalized approaches to combatting cancer and improving patient outcomes.

Related terms

Mutagenesis: The process by which mutations are induced in an organism's DNA, often leading to genetic variation or diseases, including cancer.

Apoptosis: A programmed cell death process that eliminates damaged or dysfunctional cells, acting as a protective mechanism against the development of cancer.

Oncogenes: Genes that have the potential to cause cancer when mutated or expressed at high levels; their activation can be influenced by defective DNA repair mechanisms.