SARC028 Samples Reveal an Interplay between TGF-β, IFN Signaling, and Low HLA Class I Expression as Contributors to Ewing Sarcoma Checkpoint Blockade Resistance.

ABSTRACT:

Purpose

Ewing sarcoma, in contrast to some adult sarcoma subtypes, generally does not respond to single-agent immunotherapy targeting PD1. The features of Ewing sarcoma that preclude the effectiveness of immunotherapy remain largely unknown. To address this question, we utilized biopsies from patients with Ewing sarcoma obtained before and after pembrolizumab (anti-PD1) therapy from the phase II clinical trial SARC028 to interrogate the Ewing tumor microenvironment and features associated with resistance to checkpoint inhibition.

Experimental design

We utilized multiplexed immunofluorescence, spatial proteomics, and spatial transcriptomics to analyze paired pretreatment and 8-week posttreatment biopsy specimens from patients with Ewing sarcoma enrolled in SARC028.

Results

SUBMITTER: Daley JD 

PROVIDER: S-EPMC12402801 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature