PARP1 and breast neoplasm: The slow proliferation of HCC1395 cells and their higher genomic instability and higher apoptotic activity under basal conditions as indicated in Figures 2B, C and Additional file 6: Figure S5 may further impact on these endpoints and, given the heterogeneous background of breast tumours, additional studies of p.R215W carriers will be needed to fully elucidate this aspect and clarify whether they could perhaps benefit from treatment with PARP1 inhibitors.