Tumor-specific neoantigen and tumor-associated antigen (TSA/TAA)

Patient-specific tumor-associated antigens (TAAs) and neoantigens (TSAs) are peptides derived from intracellular or membrane proteins that are processed and presented on the cell surface by Major Histocompatibility Complex (MHC) molecules. Neoantigens arise from somatic mutations unique to an individual's tumor, such as single-nucleotide variants or indels, making them highly immunogenic as they bypass central thymic tolerance. In contrast, TAAs are self-proteins that are overexpressed or selectively expressed in tumors (e.g., cancer-testis antigens) but may also be present in healthy tissues at lower levels. These MHC-presented complexes are the primary targets for personalized cancer immunotherapies, including neoantigen-based mRNA vaccines and T-cell receptor (TCR) engineered T-cell therapies. By specifically recognizing these "non-self" or "aberrant-self" signals, the immune system can selectively eliminate malignant cells while sparing normal tissue. However, the effectiveness of targeting these antigens can be limited by tumor heterogeneity, MHC downregulation, and the immunosuppressive tumor microenvironment. Clinical development in this area relies heavily on advanced bioinformatics and sequencing to identify the most immunogenic and clonal targets for each patient.

Other names

NeoantigensTumor-specific antigensTumor-associated antigensCancer-testis antigensMHC-presented peptidesPrivate antigensPublic shared antigensTumor-specific neoantigens

Induction of antigen-specific T-cell responses (CD8+ and CD4+) to recognize and lyse tumor cells presenting specific peptides on MHC molecules.