ERBB2 and neoplasm: Examining the biological activity of anti-P467 IgG antibodies in inhibiting the proliferation of Her-2-overexpressing cell line SK-BR-3, our results also indicate that the induced antibodies possess specific anti-tumor properties and when combined with Herceptin® the inhibitory capacity is significantly higher than by Herceptin® alone suggesting polyclonal and additive anti-proliferative antibody responses against Her-2/neu by our hybrid peptide P467.