Owing to this property, unusual among intracellular pathogens, L. monocytogenes has been used as a vector to generate cell-mediated immunity against a wide range of pathogen antigens: influenza nucleoprotein (NP), HPV E7, HIV gag, simian immunodeficiency virus (SIV) env, tumour antigens tyrosinase-related protein (trp)-2 and human epidermal growth factor receptor (HER)-2/neu in preclinical experiments by normally i.v. injection. The gene discussed is ERBB2; the disease is neoplasm.