Patient-specific tumor neoantigen–Major Histocompatibility Complex class I (MHC-I) complex (NeoAg-MHC-I)

The patient-specific tumor neoantigen–Major Histocompatibility Complex (MHC) class I complex is a unique molecular target formed by the presentation of mutated peptide fragments on the surface of malignant cells. These neoantigens are derived from somatic mutations—such as single nucleotide variants, insertions, or deletions—that are entirely absent from the patient's normal genome, providing a high degree of tumor specificity (Nature Reviews Cancer, 2020). The complex is recognized by the T-cell receptors (TCRs) of CD8+ cytotoxic T lymphocytes, which is the fundamental mechanism for the immune system's ability to identify and eliminate cancer cells (Science, 2017). Because these targets are unique to each individual, they form the basis for personalized immunotherapy strategies, including neoantigen-based mRNA or peptide vaccines and adoptive TCR-T cell therapies (NEJM, 2019). The clinical efficacy of targeting these complexes is often linked to the tumor mutational burden and the stability of the peptide-MHC binding (Cell, 2018). However, challenges such as tumor heterogeneity and the downregulation of MHC molecules by the tumor to evade immune detection remain significant hurdles in the development of these therapies (Nature, 2017). Furthermore, the identification of these complexes requires advanced bioinformatic pipelines to predict which mutations will be successfully processed and presented (Frontiers in Immunology, 2021). Successful targeting of the neoantigen-MHC complex represents a shift toward truly personalized precision oncology.

Other names

Tumor-specific antigen-MHC complexNeoepitope-HLA complexTSA-MHC-I complexMutated peptide-MHC complexPersonalized neoantigen-HLA complex

The complex serves as a ligand for the T-cell receptor (TCR) on CD8+ cytotoxic T lymphocytes. Upon binding, it triggers the formation of an immunological synapse, leading to T-cell activation, secretion of perforins and granzymes, and the subsequent apoptotic death of the tumor cell (Nature Reviews Cancer, 2020; Science, 2017).