MHC Class I Antigens In Malignant Cells

Abnormal expression of MHC class I molecules in malignant cells is a frequent occurrencethat ranges from total loss of all class I antigens to partial loss of MHC specific haplotypes or alleles. Different mechanisms are described to be responsible for these alterations, requiring different therapeutic approaches.A complete characterization of these molecular defects is important for improvement of the strategies for the selection and follow-up of patients undergoing T-cell based cancer immunotherapy. Precise identification of the mechanism leading to MHC class I defects will help to develop new personalized patient-tailored treatment protocols.There is significant new researchon the prevalence of various patterns of MHC class I defects and the underlying molecular mechanisms in different types of cancer. In contrast, few data isavailable on the changes in MHC class I expression during the course of cancer immunotherapy, but the authors have recently made discoveries thatshowtheprogression or regression of a tumor lesion in cancer patients undergoing immunotherapy depends on the molecular mechanism responsible for the MHC class I alteration and not on the type of immunotherapy used. According to this notion, the nature of the preexisting MHC class I lesion in the cancer cell has a crucial impact ondetermining the final outcome of cancer immunotherapy.This SpringerBrief will presenthow MHC class 1 is expressed, explain its role in tumor progression, and its role in resistance to immunotherapy.