Finally, another possible explanation could be that patients with hormone receptor-positive breast cancer benefit from extended periods of 5 to 10 years of endocrine therapy and patients with HER2-positive breast cancer receive anti-HER2-targeted therapies, whereas patients with triple-negative breast cancer rely predominantly on acute interventions such as surgery, chemotherapy and radiation owing to the absence of specific receptors (see Box 1). This evidence concerns the gene ERBB2 and breast cancer.