Building on this unique feature, we have developed synthetic chaperone vaccines by complexing large HSPs (e.g., hsp110, grp170) non-covalently with clinically relevant tumor protein antigens (e.g., gp100, HER-2/Neu) and demonstrated their potent immunotherapeutic activities involving CD8+ cytotoxic T lymphocytes (CTLs) in multiple preclinical cancer models (4–8). The gene discussed is ERBB2; the disease is cancer.