We hereby present the unique case of a non-smoker young patient without personal cardiovascular risk factors and no familiar history of ischemic myocardiopathy or dyslipidemia, affected by early-stage hormone receptor-positive (HR+)/HER2+ breast cancer who developed sudden hypotension and severe oppressive chest pain with electrocardiographic abnormalities and troponin elevation consistent with an acute coronary syndrome compatible with a type I KS, following paclitaxel administration (Fig. 1). The gene discussed is ERBB2; the disease is breast carcinoma.