ERBB2 and cancer: Similarly, we have shown that unfractionated PBMC from HER2/neu-vaccinated cancer patients can give rise to enriched HER2-specific CD4+ and CD8+ T-cells, when such PBMC are cultured with the vaccination peptides as well as with exogenous recombinant IL-12 and IL-2, then further expanded by polyclonal anti-CD3/CD28 stimulation [23, 24].