BRCA1 and neoplasm: To address this, we established xenograft tumours in CB17‐SCID mice using BRCA1‐compromised MDA‐MB‐436 mammary breast cancer cells (Fig 5), which carry an inactivating 5,396+1G>A mutation in BRCA1 gene (Elstrodt et al, 2006), and monitored their long‐term (up to 63 days) response to pyridostatin alone, or in combination with other drugs.