SS18-SSX fusion protein-derived neoantigen peptide (SS18-SSX neoantigen)

The SS18-SSX fusion protein-derived neoantigen peptide is a tumor-specific target arising from the pathognomonic t(X;18)(p11;q11) chromosomal translocation, which is present in over 95% of synovial sarcoma cases (Nielsen et al., 2002). This translocation fuses the SS18 gene on chromosome 18 with an SSX gene (SSX1, SSX2, or SSX4) on the X chromosome, resulting in a chimeric protein with a unique amino acid sequence at the fusion junction. Short peptide fragments spanning this junction are processed and presented by Human Leukocyte Antigen (HLA) molecules, such as HLA-A*02:01 or HLA-A*24:02, on the surface of tumor cells (Sato et al., 2002). Because this sequence is entirely absent from the normal human proteome, it represents a highly specific neoantigen for immunotherapy. Therapeutic strategies targeting this peptide include peptide-based vaccines and adoptive cell therapies using T-cell receptors (TCRs) engineered to recognize the peptide-HLA complex (Kawaguchi et al., 2012). These approaches aim to harness the precision of the immune system to selectively eliminate synovial sarcoma cells while minimizing off-target effects on healthy tissues.

Other names

SYT-SSX fusion peptideSS18-SSX junction peptideSynovial sarcoma fusion neoantigen

T-cell receptor (TCR) mediated recognition of the fusion peptide presented on Human Leukocyte Antigen (HLA) molecules, leading to cytotoxic T-lymphocyte activation and tumor cell lysis.