1. Academic Validation
  2. Evolutionary Pressures Shape Undifferentiated Pleomorphic Sarcoma Development and Radiotherapy Response

Evolutionary Pressures Shape Undifferentiated Pleomorphic Sarcoma Development and Radiotherapy Response

  • Cancer Res. 2025 Mar 14;85(6):1162-1174. doi: 10.1158/0008-5472.CAN-24-3281.
Erik S Blomain 1 Shaghayegh Soudi 2 Ziwei Wang 2 Anish Somani 2 Ajay Subramanian 2 Serey C L Nouth 2 Eniola Oladipo 2 Christin New 3 Deborah E Kenney 3 Neda Nemat-Gorgani 2 Thomas Kindler 4 5 Raffi S Avedian 3 Robert J Steffner 3 David G Mohler 3 Susan M Hiniker 2 Alexander L Chin 2 Anusha Kalbasi 2 Michael S Binkley 2 Marius Fried 4 Matthias M Gaida 5 6 Matt van de Rijn 7 Everett J Moding 2 8
Affiliations

Affiliations

  • 1 Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania.
  • 2 Department of Radiation Oncology, Stanford University, Stanford, California.
  • 3 Department of Orthopedic Surgery, Stanford University, Stanford, California.
  • 4 Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany.
  • 5 TRON, Translational Oncology at the University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany.
  • 6 Institute of Pathology, University Medical Center Mainz, Johannes Gutenberg University Mainz, Mainz, Germany.
  • 7 Department of Pathology, Stanford University, Stanford, California.
  • 8 Stanford Cancer Institute, Stanford University, Stanford, California.
Abstract

Radiotherapy is an integral component in the treatment of many types of Cancer, with approximately half of patients with Cancer receiving radiotherapy. Systemic therapy applies pressure that can select for resistant tumor subpopulations, underscoring the importance of understanding how radiation impacts tumor evolution to improve treatment outcomes. We integrated temporal genomic profiling of 120 spatially distinct tumor regions from 20 patients with undifferentiated pleomorphic sarcomas (UPS), longitudinal circulating tumor DNA analysis, and evolutionary biology computational pipelines to study UPS evolution during tumorigenesis and in response to radiotherapy. Most unirradiated UPSs displayed initial linear evolution, followed by subsequent branching evolution with distinct mutational processes during early and late development. Metrics of genetic divergence between regions provided evidence of strong selection pressures during UPS development that further increased during radiotherapy. Subclone abundance changed after radiotherapy with subclone contraction tied to alterations in calcium signaling, and inhibiting calcium transporters radiosensitized sarcoma cells. Finally, circulating tumor DNA analysis accurately measured subclone abundance and enabled noninvasive monitoring of subclonal changes. These results demonstrate that radiation exerts selective pressures on UPSs and suggest that targeting radioresistant subclonal populations could improve outcomes after radiotherapy. Significance: Radiotherapy mediates tumor evolution by leading to the expansion of resistant subclonal Cancer cell populations, indicating that developing approaches to target resistant subclones will be crucial to improve radiotherapy response.

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