DNA DAMAGE AND REPAIR

L10: DNA DAMAGE & REPAIR [17/10/2022]



I. DNA REPAIR & CANCER

 Each cell is thought to undergo >20,000 DNA damaging events and >10,000 replication
errors per day
 What is the connection between DNA repair and cancer?
 Genomic instability:
 It is linked with human cancers
 Problems with DNA repair led to genome instability



II. CANCER & GENOMIC INSTABILITY

 Cancer cells show genomic instability:
 Subtle sequence changes – cause mutations
 Dramatic karyotypic changes – gains and losses of complete or partial chromosomes,
chromosome rearrangements

 In some cases, still trying to determine what is cause and effect.
 Does genome instability cause cancer?
 Do cancerous cells have greater genome instability?



III. TYPES OF DNA DAMAGE:

, IV. MAJOR SOURCES OF DNA DAMAGE




V. MAJOR TYPES OF DNA REPAIR

 Various DNA repair pathways have evolved to maintain genomic stability
- Excision repair
 Base excision repair (BER)
 Nucleotide excision repair (NER)