ERBB2 and breast carcinoma: Regarding breast cancer subtypes by immunohistochemistry (Fig 2E–2H), 31.6% (n = 216) of patients were a luminal-A subtype, 12.4% (n = 85) were luminal-B subtype, 37.9% (n = 259) were HER2 subtype, and 18.0% (n = 123) were triple-negative subtype.