Integrative Analysis of Pleomorphic Dermal Sarcomas Reveals Fibroblastic Differentiation and Susceptibility to Immunotherapy

Clin Cancer Res. 2020 Nov 1;26(21):5638-5645. doi: 10.1158/1078-0432.CCR-20-1899. Epub 2020 Aug 17.

Abstract

Purpose: Pleomorphic dermal sarcoma (PDS) is a rare malignant cutaneous tumor with an unknown cell of origin. Locally defined tumors can be treated by curative excisions, whereas advanced stages of the disease are difficult to treat, using standard regimens.

Experimental design: We performed whole-exome sequencing on a cohort of 28 individuals and corresponding transcriptomic analysis on 21 patients, as well as quantitative IHC image analysis on 27 patients.

Results: PDS exhibits a universally high mutational load (42.7 mutations/mega base) with an inflamed, immunogenic tumor microenvironment. Three cases of PDS showed response to immune checkpoint blockade. Local mutation rate variation together with mRNA expression data demonstrate that PDS form a distinct entity, with PDGFRB as a lineage marker. In addition, we found that PDS is of mesenchymal, fibroblastic differentiation.

Conclusions: PDS is of fibroblastic differentiation and exhibits a strong susceptibility to immunotherapy, including a high mutational burden and an inflamed tumor microenvironment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics
  • Cell Differentiation / genetics
  • Female
  • Fibroblasts / cytology
  • Fibroblasts / immunology
  • Genetic Predisposition to Disease / genetics
  • Humans
  • Immune Checkpoint Inhibitors / therapeutic use
  • Immunologic Factors / genetics
  • Immunotherapy*
  • Male
  • Middle Aged
  • Mutation / genetics
  • Sarcoma / drug therapy
  • Sarcoma / genetics*
  • Sarcoma / immunology
  • Sarcoma / pathology
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / immunology
  • Skin Neoplasms / pathology
  • Transcriptome / genetics*
  • Tumor Microenvironment / drug effects
  • Tumor Microenvironment / genetics
  • Whole Exome Sequencing

Substances

  • Biomarkers, Tumor
  • Immune Checkpoint Inhibitors
  • Immunologic Factors