The NCOA4-RET fusion was detected in an ER+ /PR−/HER2+ breast cancer and results from tandem duplication with breakpoints in NCOA4 exon 8 and RET intron 11; includes the NCOA4 exons encoding a putative coiled-coil domain and the RET exons encoding the kinase domain and therefore retains all the functional domains characteristic of activating NCOA4-RET fusion proteins that have been studied in PTC and NSCLC3,17,20,26 (Fig. 1e). Here, ERBB2 is linked to breast carcinoma.