Clinical significance of MART-1 and HLA-A2 expression and CD8+ T cell infiltration in melanocytic lesions in HLA-A2 phenotype patients

MART-1 is a good candidate antigen for immunotherapy against HLA-A2 patients with melanoma, since it is a highly immunogenic antigen recognized by HLA-A2 and HLA-B45 restricted CD8+ cytotoxic T cells and expressed in the majority of melanoma lesions. In the present study the expression of MART-1 and HLA-A2 on melanocytic cells and CD8+ T cell infiltration was immunohistochemically analyzed. MART-1 was expressed in most melanocytic lesions, while HLA-A2 was down-regulated with melanoma disease progression. Furthermore, concomitant down-regulation of MART-1 and HLA-A2 in melanoma cells was corrrelated with poor prognosis. These findings suggest both MART-1 and HLA-A2 expression in melanoma lesions should be analyzed for selection of patients eligible for MART-1 based immunotherapy and monitoring for emergence of melanoma cells resistant to T cell therapy.