Prevalence and Prognostic Implications of PD-L1 Expression in Soft Tissue Sarcomas

Pathol Oncol Res. 2021 Jul 1:27:1609804. doi: 10.3389/pore.2021.1609804. eCollection 2021.

Abstract

Background: PD-L1 expression differs from 19 to 92% in various cancer subtypes. Its expression carries a worse prognostic value in various malignancies and could also be used as a predictive marker for immune checkpoint inhibitor response. This study aimed to explore the prevalence of PD-L1 expression in soft tissue sarcomas and the correlation of PD-L1 expression with clinicopathological features. Patients and Methods: The tissue samples of 50 patients with STS were tested for PD-L1 expression using immunohistochemistry (IHC). We followed a 6-step proportional scoring system. The patients were treated at Ain Shams University Hospital from 2011 to 2017. We also explored the correlation of PD-L1 expression with different clinical features of the patients. The chi-square test was used to calculate the differences among variables. Results: Twelve cases (24%) showed positive PD-L1 expression with the highest prevalence in rhabdomyosarcoma and desmoid tumors (2/2 and 2/3 cases, respectively), followed by GIST in 2/4 cases and liposarcoma in 3/11 cases. Patients with positive PD-L1 expression showed a trend for worse survival, with a median overall survival of 11 months vs. 19 months for patients with negative PD-L1 expression (p-value = 0.1) and a mean PFS of 6 months vs. 11 months for patients with negative PD-L1 expression (p-value = 0.1). However, these findings did not reach statistical significance. Conclusion: Although the results did not reach statistical significance due to the small number of cases, PD-L1 expression could represent a prognostic factor for poor outcome. Larger clinical trials are recommended for the validation of PD-L1 as a poor prognostic biomarker.

Keywords: PD-L1 expression; biomarker; prevalence; prognosis; soft tissue sarcomas.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • B7-H1 Antigen / metabolism*
  • Biomarkers, Tumor / metabolism*
  • Chemoradiotherapy / mortality*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / epidemiology
  • Neoplasm Recurrence, Local / metabolism
  • Neoplasm Recurrence, Local / pathology*
  • Neoplasm Recurrence, Local / therapy
  • Prevalence
  • Prognosis
  • Retrospective Studies
  • Sarcoma / epidemiology
  • Sarcoma / metabolism
  • Sarcoma / pathology*
  • Sarcoma / therapy
  • Survival Rate
  • Young Adult

Substances

  • B7-H1 Antigen
  • Biomarkers, Tumor
  • CD274 protein, human