Importantly, genetically engineered T lymphocytes expressing very high affinity self/tumor-specific TCRs also target normal tissues expressing the cognate antigen (e.g., melanocytes in the skin, eye, and ear for Melan-A-specific T cells and neurons for MAGE-A3-specific T cells), and can mount harmful cytotoxic immune responses in vivo (Johnson et al., 2009; Morgan et al., 2013). The gene discussed is MLANA; the disease is neoplasm.