Major histocompatibility complex class I chain-related A and B molecules and their potential role in virus-associated cancers

Infections with certain viruses are strong risk factors for specific cancers. The human major histocompatibility complex class I chain-related genes A (MICA) and B (MICB) are polymorphic, non-classical major histocompatibility complex class I genes located within the human leukocyte antigen region. Polymorphisms in these genes have been associated with susceptibility and outcomes of several virus-associated cancers. The underlying mechanisms involve modulation of natural killer cell- and CD8+ T cell-mediated cytotoxicity by disrupting the natural killer group 2-member D-MICA/B axis. The resulting soluble forms of both MICA and MICB have recently gained attention as potential predictive biomarkers for virus-induced malignancies and disease severity. Therapeutic strategies targeting this axis show considerable promise. This minireview summarizes the genetics and biology of MICA and MICB, highlighting their emerging importance in the pathogenesis of virus-associated cancers.