ERBB2 and breast cancer: Here, in a study including 11 publicly available data sets of breast cancer and information on altogether 2423 patients, we found that the 18-gene vascular invasion signature showed strong associations with features of aggressive breast cancer such as high tumor grade, hormone receptor negativity, HER2 positive tumors, presence of a basal-like phenotype, reduced patient survival and response to neoadjuvant chemotherapy.