The SUM149PT breast cancer cell line was chosen for this study as a relevant model for studying PARPi activity, since it harbours a hypomorph BRCA1 allele with a mutation in the exon 11 of the gene (2288delT causing partial exon 11 skipping (Δ11q)) [22, 39–41]. This evidence concerns the gene BRCA1 and breast carcinoma.