ERBB2 and breast cancer: MCBC is not common and the incidence has been reported between 1.4% and 11.8%.2 Hormonal receptor (HR)-negative first BC has a higher incidence of contralateral BC compared with HR-positive first BC.2, -4 Human epidermal growth factor receptor 2 (HER-2)-positive first BC has a higher incidence of contralateral BC compared with HER-2-negative first BC.2,3 However, there are very few reported cases of contralateral metachronous triple positive BC.