It has been previously reported that PARP1 also has a role in repair of double strand breaks, such as non-homologous end joining (NHEJ) and microhomology-mediated end joining (MMEJ), which are error prone DNA repair pathways39, 40, therefore overexpression of PARP1 in BARD1β expressing cells might also increase genomic stability and cancer. This evidence concerns the gene PARP1 and cancer.