Frameshift peptide neoantigen presented by HLA molecule (FSP neoantigen (context-dependent, not universally standardized))

Frameshift peptide neoantigens are abnormal peptides generated from frameshift mutations (insertions/delations in coding microsatellites) most commonly observed in microsatellite instability-high cancers. These peptides are processed and presented on the cell surface by HLA molecules (MHC class I or II) and are recognized as non-self by the immune system, making them highly immunogenic. As a result, they are considered promising targets for precision immunotherapies including personalized cancer vaccines and adoptive cell therapies. Exploiting FSP neoantigens presented by HLA molecules allows for highly specific antitumor responses with reduced risk of targeting normal tissue, but these therapies face technical and translational challenges due to tumor heterogeneity, immunoediting, and the need for precise patient selection. Note: This entry covers a molecular class (peptide neoantigen–HLA complex) rather than a singular gene/protein. Clinical translation typically involves customized identification and targeting for each patient or tumor subtype.

Other names

Frameshift peptide neoantigenFSP neoepitopeNeoantigen peptide (when context refers to frameshift mutation origin)Tumor-specific neoantigen (context dependent, but not exclusive to FSP origin)

Induction of tumor-specific T-cell responses, leading to immune recognition and killing of tumor cells expressing FSP neoantigen-HLA complexes Immune checkpoint inhibitors may enhance responses by unleashing FSP neoantigen-specific T cells