BRCA1 and breast cancer: We further investigated the relationship between BRCA1 methylation status, treatment exposure and platinum sensitivity, using four distinct TNBC PDX models, WHIM68, WHIM69, WHIM74 and WHIM75, established from sequential breast cancer biopsies and surgical specimens of the same patient donor, hereby referred to as the WHIM PDX longitudinal series (Fig. 3D).