Figure 1.

DNA damage may lead to single strand breaks; PARP detects the DNA lesion in the single strand break. PARP takes part in recruiting repair factors to the single stranded DNA lesion site and promotes the activity of enzymes during the repair. PARP inhibitors function by reducing the catalytic activity of PARPs and can help prevent single strand break repair which can lead to double strand breaks which can’t be repaired by BRCA mutant tumors or can trap PARP at the site of DNA damage via preventing PARP detachment from DNA. This then prevents the replication fork from progressing and leads to cell death unless this damage is repaired.