PARP1 and cancer: There are currently many clinical trials being undertaken with different inhibitors of PARP namely olaparib, rucaparib, veliparib, niraparib, and talazoparib, in a range of cancers (De Bono et al., 2017; Jiang et al., 2019; Tuli et al., 2019), and their capacity to act as chemo/radio-sensitizers is well documented.