PAX3-FOXO1 fusion protein-derived neoantigen (PAX3-FOXO1 neoantigen)

PAX3-FOXO1 fusion protein-derived neoantigens are tumor-specific peptides that arise from the unique amino acid sequence at the junction of the PAX3 and FOXO1 proteins (NIH, 2013; NIH, 2018). This fusion is the result of a characteristic t(2;13)(q35;q14) chromosomal translocation found in approximately 60% of alveolar rhabdomyosarcoma (ARMS) cases (NIH, 2015; NIH, 2023). Because the fusion sequence is entirely absent in normal tissues, these neoantigens represent highly specific targets for immunotherapy, minimizing the risk of off-target toxicity (NIH, 2018; Frontiers in Oncology, 2021). Therapeutic strategies under investigation include dendritic cell vaccines pulsed with breakpoint peptides and T-cell receptor (TCR) engineered T-cell therapies (NIH, 2018; NIH, 2025). While these approaches have shown the ability to elicit specific cytotoxic T-lymphocyte (CTL) responses in preclinical and early clinical pilot studies, challenges remain (NIH, 2013; NIH, 2025). These include the high degree of HLA restriction (e.g., HLA-B7), the relatively low and transient immunogenicity of the peptides, and the potential for tumor recurrence through antigen-independent mechanisms (NIH, 2013; NIH, 2025). Despite these hurdles, targeting the PAX3-FOXO1 neoantigen remains a promising avenue for developing precision treatments for this aggressive pediatric cancer (NIH, 2018; NIH, 2023).

Other names

PAX3-FKHR fusion protein neoantigenPAX3-FOXO1 breakpoint peptidePAX3-FOXO1 junctional peptidePAX3-FOXO1 fusion-specific antigenPAX3-FOXO1 breakpoint-derived neoantigen

T-cell mediated immunotherapy targeting tumor-specific fusion protein sequences