"Hard" and "soft" lesions underlying the HLA class I alterations in cancer cells: implications for immunotherapy.
The ability of cancer cells to escape from the natural or immunotherapy-induced antitumor immune response is often associated with alterations in the tumor cell surface expression of Major Histocompatibility Complex (MHC) Class I antigens. Considerable knowledge has been gained on the prevalence of various patterns of MHC Class I defects and the underlying molecular mechanisms in different types of cancer. In contrast, few data are available on the changes in MHC Class I expression happening during the course of cancer immunotherapy. We have recently proposed that the progression or regression of a tumor lesion in cancer patients undergoing immunotherapy could be predetermined by the molecular mechanism responsible for the MHC Class I alteration and not by the type of immunotherapy used, i.e., interleukin-2 (IL-2), Bacillus Calmette-Guèrin (BCG), interferon-alpha (IFN-alpha), peptides alone, dendritic cells loaded with peptides, protein-bound polysaccharide etc. If the molecular alteration responsible for the changes in MHC Class I expression is reversible by cytokines ("soft" lesion), the MHC Class I expression will be upregulated, the specific T cell-mediated response will increase and the lesion will regress. However, if the molecular defect is structural ("hard" lesion), the MHC Class I expression will remain low, the escape mechanism will prevail and the primary tumor or the metastatic lesion will progress. According to this idea, the nature of the preexisting MHC Class I lesion in the cancer cell has a crucial impact determining the final outcome of cancer immunotherapy. In this article, we discuss the importance of these two types of molecular mechanisms of MHC Class I-altered expression.
Garrido
Federico
F
Departamento de Bioquímica, Universidad de Granada, Granada, Spain. federico.garrido.sspa@juntadeandalucia.es
Cabrera
Teresa
T
Aptsiauri
Natalia
N
D019496:Cancer Vaccines / Q000627:therapeutic use; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007167:Immunotherapy; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D019139:Tumor Escape / Q000502:physiology*
D019496:Cancer Vaccines; D015395:Histocompatibility Antigens Class I