The first-in-human TCR-T clinical trials in solid cancer followed the footsteps of TIL therapies and TCR were selected for specificity based on clinically relevant responses seen with TIL therapy of melanoma patients, initially including the melanoma antigen recognized by T cells 1 (MART-1) and melanoma glycoprotein 100 (gp100); both are differentiation antigens present in pigmented cells, like melanocytes, but are highly over-expressed in melanomas (19). The gene discussed is PMEL; the disease is melanoma.