<P> The prevalence of DNA damage response mutations differs across cancer types; for example, 30% of breast invasive carcinomas have mutations in genes involved in homologous recombination . In cancer, downregulation is observed across all DNA damage response mechanisms (base excision repair (BER), nucleotide excision repair (NER), DNA mismatch repair (MMR), homologous recombination repair (HR), non-homologous end joining (NHEJ) and translesion DNA synthesis (TLS). As well as mutations to DNA damage repair genes, mutations also arise in the genes responsible for arresting the cell cycle to allow sufficient time for DNA repair to occur, and some genes are involved in both DNA damage repair and cell cycle checkpoint control, for example ATM and checkpoint kinase 2 (CHEK2)--a tumor suppressor that is often absent or downregulated in non-small cell lung cancer . </P> <Table> <Tr> <Th> </Th> <Th> HR </Th> <Th> NHEJ </Th> <Th> SSA </Th> <Th> FA </Th> <Th> BER </Th> <Th> NER </Th> <Th> MMR </Th> </Tr> <Tr> <Td> ATM </Td> <Td> x </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> ATR </Td> <Td> x </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> PAXIP </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> RPA </Td> <Td> x </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> </Td> </Tr> <Tr> <Td> BRCA1 </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> BRCA2 </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> RAD51 </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> RFC </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> </Tr> <Tr> <Td> XRCC1 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> </Tr> <Tr> <Td> PCNA </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> x </Td> <Td> x </Td> </Tr> <Tr> <Td> PARP1 </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> ERCC1 </Td> <Td> x </Td> <Td> </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> <Td> x </Td> <Td> </Td> </Tr> <Tr> <Td> MSH3 </Td> <Td> x </Td> <Td> </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> x </Td> </Tr> </Table> <Tr> <Th> </Th> <Th> HR </Th> <Th> NHEJ </Th> <Th> SSA </Th> <Th> FA </Th> <Th> BER </Th> <Th> NER </Th> <Th> MMR </Th> </Tr> <Tr> <Td> ATM </Td> <Td> x </Td> <Td> x </Td> <Td> x </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr>

Can dna polymerase editing function remove dna adducts