AUTHOR=KELANY MOHAMED , FE Barth Thomas , Salem Dina , Shakweer Marwa M.

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

JOURNAL=Pathology and Oncology Research

VOLUME=27

YEAR=2021

URL=https://www.por-journal.com/journals/pathology-and-oncology-research/articles/10.3389/pore.2021.1609804

DOI=10.3389/pore.2021.1609804

ISSN=1532-2807

ABSTRACT=<p><bold>Background:</bold> 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.</p><p><bold>Patients and Methods:</bold> 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.</p><p><bold>Results:</bold> 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 (<italic>p</italic>-value = 0.1) and a mean PFS of 6 months vs. 11 months for patients with negative PD-L1 expression (<italic>p</italic>-value = 0.1). However, these findings did not reach statistical significance.</p><p><bold>Conclusion:</bold> 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.</p>