In 2003 our group has demonstrated a differential chemosensitivity profile in vitro of BRCA1-mutated HCC1937 breast cancer cells with bi-allelic loss as compared to the derivative clone HCC1937WT, where the BRCA1 expression has been reconstituted by transfection of a BRCA1 full length cDNA [25]. Here, BRCA1 is linked to breast cancer.