ERBB2 and cancer: A further bridge toward human cancer was recently provided by novel immunodeficient models, like Rag2−/−;Il2rg−/− mice, which are permissive for metastatic spread of human HER-2+ cancer cells and can be engrafted with a functional human immune system, allowing for the first time the study of vaccines against oncoantigens to elicit human immune responses against human cancer cells in vivo.