We further sought to investigate whether inter‐lesion heterogeneity was associated with clinical or histopathological variables, such as age at diagnosis, axillary lymph node involvement, tumour size, molecular subtype of the tumour based on ER and HER2 status, histological grade, number of multifocal lesions, largest distance between lesions, presence of in situ component, and lymphovascular invasion. The gene discussed is ERBB2; the disease is neoplasm.