In situ T cells in melanoma.
During the past decade new insights have been gained into the role of T lymphocytes in the host's immune response to cancer in general and to melanoma in particular. Several melanoma-associated antigens (MAA) recognized by T cells have been characterized, and a number of HLA class I- and class II-restricted peptides have been identified. These antigens can be divided into three different groups: tumor-associated testis-specific antigens, melanocyte differentiation antigens, and mutated or aberrantly expressed antigens. These proteins give rise to several antigenic peptides. The number of known melanoma-associated peptides that can induce killing by cytotoxic T-lymphocytes (CTL) exceeds 30 and is still increasing. In line with these findings, clinical data indicate that the immune system is essential in the control of tumor growth. A brisk infiltration of lymphocytes is associated with a favorable prognosis, and complete or partial regression of primary melanoma occurs quite frequently. Furthermore, immunomodulatory therapies have accomplished complete or partial tumor regression in a number of patients. However, the immune response is in most cases inadequate to control tumor growth as tumor progression often occurs. Hence, the coexistence of a cellular immune response in melanoma lesions, demonstrated by the presence of clonally expanded T cells, remains a major paradox of tumor immunology. In the present paper we review current knowledge regarding tumor infiltrating lymphocytes (TIL) in melanoma and discuss possible mechanisms of escape from immune surveillance.
thor Straten
P
P
Department of Tumor Cell Biology, Danish Cancer Society, Copenhagen, Denmark.
Becker
J C
JC
Guldberg
P
P
Zeuthen
J
J
D015703:Antigens, CD / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000276:immunology; D016130:Immunophenotyping; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D019139:Tumor Escape / Q000276:immunology
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D017252:CD3 Complex; D007135:Immunoglobulin Variable Region; D016693:Receptors, Antigen, T-Cell, alpha-beta