ERBB2 and breast carcinoma: In addition, whereas previous studies underlined the intrinsic proliferative/invasive disadvantage of full-length HER2 mammary carcinoma cells in comparison to Delta16, our results indicate that microenvironmental interactions, e.g. with tumor vasculature [29], could counterbalance this disadvantage by granting preferential access to the bloodstream and to systemic dissemination, eventually resulting in net metastatic diffusion of equal entity.