To generate antitumor T cells with optimal affinity of T cell receptor (TCR) to cancer-associated antigens, Obenaus et al. (2015) reported the potential of using antigen-negative humanized mice to generate T cells with a diverse human TCR repertoire and isolated the TCR specific to cancer antigens MAGE-A1 and NY-ESO-1, which have better affinity compared to human-derived TCRs [14]. The gene discussed is MAGEA1; the disease is cancer.