Tumor-infiltrating lymphocytes (TILs) were grown from four distinct anatomic sites from a patient with metastatic melanoma. The metastatic sites included a tumor-involved lymph node, a subcutaneous lesion obtained from the chest wall, a portion of bowel, and adrenal gland. TILs grown from each anatomic site over the course of 20 days in the presence of 6,000 IU/ml recombinant interleukin-2 exhibited comparable growth rates. Between days 30 and 45, the TILs were a mixture of CD3+ CD4+ and CD3+ CD8+ lymphocytes expressing the alpha beta form of the T-cell receptor. TILs derived from each anatomic site specifically lysed autologous tumor obtained from all four anatomic sites. In fine specificity analysis, the TILs exhibited human leukocyte antigen (HLA-A2)-restricted lysis of fresh tumor targets and cultured melanoma cell lines. Each TIL recognized a product of the MART-1 gene, and specifically, the monomer peptide MART-1(27-35). Thus lymphocytes reactive with the MART-1 melanoma antigen appeared to be widely distributed in diverse metastases in this patient. This information, along with previous data on the reactivity of multiple patients to this antigen, attests to its dominance in the immune reactivity of humans to melanoma.