In the 2018 updated ASCO/CAP guidelines, an ERBB2-positive breast cancer is defined by a ratio of 2 to chromosome enumeration probe 17 (CEP17) in fluorescence in situ hybridization, a copy number of 6 in ERBB2, or a score of 3 + for HER2 immunohistochemistry.[80] The Cancer Genome Atlas project has shown that there is not the same genomic profile for all HER2-positive breast cancers. Here, ERBB2 is linked to breast cancer.