ERBB2 and cancer: The low level of EMILIN1 expression, coupled with the reduced levels of the α4β1/α9β1 integrin receptors on HER2+ cancer cells, reported by others35, and the potent activity of the Δ16HER2 oncogene, may explain why we could not detect an antiproliferative effect of EMILIN1 in the tumor mass, while we could observe it in pre-neoplastic mammary glands at 11 W and 13 W.