PARP1 and cancer: Proteins such as BRCA1, BRCA2, PALB2, ATM, CHEK1, CHEK2, and RAD51 are involved in the HR repair process, while poly(ADP-ribose) polymerases 1 and 2, referred to as PARP1 and PARP2, are associated with the BER, with some of these proteins being frequently mutated in cancer patients.