BRCA1 and gastric cancer: For example, breast tumours from patients with germline mutations in BRCA1 or BRCA2 harbour a greater number of clonal mutations compared with BRCA1/2 wild-type tumours (Nik-Zainal et al, 2012), and in a study of gastric cancer, an association between ATM loss and microsatellite instability has been demonstrated (Kim et al, 2014).