Efforts to further adjuvant the immune system through cancer vaccines had, unfortunately, yielded largely disappointing results in Phase 3 trials due to limited ability of peptide vaccines to induce CD8+ T-cell responses, induction of T cells with a restricted repertoire insufficient to counter cancer cells with heterogeneous epitope expression profiles, and inadequate induction of additional arms of the immune systems (CD4+ T cells and B cells) for synergistic tumor killing (2, 3). The gene discussed is CD4; the disease is neoplasm.