BRCA1 and breast neoplasm: Given the interest in PARP inhibitor sensitivity in OS, we also included in the tumour cell line panel a PARP inhibitor sensitive breast tumour cell line, SUM149, with loss of function BRCA1 mutation (BRCA1 p.P724fs*12) as well as a PARP inhibitor resistant SUM149-subclone, SUM149.B1*.S, that has partially restored BRCA1 function because of a CRISPR-Cas9 mutagenesis-engineered BRCA1 intragenic reversion mutation8.