CDH1 and CDH1-related diffuse gastric and lobular breast cancer syndrome: This indicates that the addition of the loss of Tp53 does not interfere with the observed synthetic lethal effect and that dasatinib may be an option not only for the chemoprevention of DGC and LBC in germline CDH1 mutation carriers, but also the treatment of a subset of advanced tumours harbouring both CDH1 and TP53 mutations.