Additionally, in a similar TRP-1 TCR transgenic adoptive transfer model with B16 melanoma in RAG1-deficient lymphopenic hosts, the addition of OX40 agonists and the chemo-therapy cyclophosphamide enhanced tumor killing by cytotoxic CD4+ T cells, in a manner dependent on EOMES expression (Hirschhorn-Cymerman et al., 2012). The gene discussed is CD4; the disease is melanoma.