Examples include a deletion in a breast cancer that removes the ligand-binding domain [50] and three further inactivating deletions [51]: fusions that retain only the 5′ end of NRG1, e.g. two described by Drilon et al. [8], and 3′ fusions that splice in at the transmembrane domain [51]. The gene discussed is NRG1; the disease is breast carcinoma.