In the human HLA A2‐restricted NY‐ESO‐1157–165 tumour system, transduced CD8+ T cells expressing TCRs with a binding dissociation constant (KD) of 84 nM were found to be cross‐reactive, while transduced CD4+ T cells only displayed off‐target effects at considerably higher affinities 30. This evidence concerns the gene CD4 and neoplasm.