Integrated Immunotherapy Target Atlas for Ewing Sarcoma.

Abstract

Background/aim: Ewing sarcoma is a fusion-driven malignancy with low tumor mutational burden, making recurrent tumor-associated antigens with favorable tumor-to-normal contrast central to immunotherapy development. We converted the Deng et al.-defined 32-gene Ewing Sarcoma Specific Signature (ESS32) into a practical target atlas by integrating tumor RNA expression with normal-tissue context, protein evidence, subcellular localization, and therapeutic accessibility.

Materials and methods: A 38-gene set was analyzed, including ESS32 and six comparator antigens (STEAP1, LINGO1, PRAME, CD99, CD276/B7-H3, and ENPP1). Eight Gene Expression Omnibus datasets (n=854 samples) were assigned predefined roles spanning tumor-versus-skeletal-muscle comparison, broad normal-organ context, EWSR1::FLI1 perturbation, tumor-only support cohorts, cell-line models, and cross-sarcoma comparison. Results were overlaid with Human Protein Atlas and published proteomic/surfaceome evidence.

Results: In GSE17674, the strongest tumor-enriched transcripts included NKX2-2, NPY1R, STEAP1, RBM11, RNF182, LIPI, CD99, STEAP2, LOXHD1, and DCDC2. Normal-tissue and compartment data substantially reordered RNA-only ranking. NKX2-2 showed the strongest Ewing-associated signal but encodes a nuclear transcription factor, favoring peptide-HLA/T-cell receptor (TCR) or vaccine development. RBM11 and LIPI emerged as high-interest intracellular/secretome-associated candidates, with an explicit epididymal/male reproductive caveat for LIPI. CD99 and NPY1R illustrated normal-cell reservoir and receptor-distribution constraints.

Conclusion: ESS32 should be interpreted as an EWSR1::FLI1-associated RNA discovery set, not as a pre-validated target panel. Practical nomination requires integration of RNA enrichment, normal-tissue distribution, protein evidence, cellular compartment, and modality compatibility before nomination of TCR, vaccine, antibody-drug conjugate (ADC), chimeric antigen receptor (CAR), radioligand, or validation-first candidates.