Related Experiment Video
Updated: May 5, 2026
Isolation and Characterization of Tumor-initiating Cells from Sarcoma Patient-derived Xenografts
Published on: June 13, 2019
Programmed-cell death ligand 1 (PD-L1) expression in equine sarcoids and squamous cell carcinoma
José Pimenta1,2,3, Justina Prada1,2,4, Isabel Pires1,2,4
1CECAV Veterinary and Animal Research Center, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal.
Background:
Sarcoids and squamous cell carcinomas (SCCs) are the most concerning equine oncological diseases. Both tumors are challenging to manage due to their invasive behavior and high prevalence of recurrences. Furthermore, SCCs have a propensity to metastasize. Programed cell-death ligand 1 (PD-L1) has been one of the main therapeutic targets for immunotherapy in various human tumors. PD-L1 research in equine tumors is scarce and more efforts are necessary to understand the potential of this biomarker as a therapeutical target.
Aim:
Evaluate the immunohistochemical expression of PD-L1 in equine sarcoids and SCC.
Methods:
Thirteen equine tumors (seven sarcoids and 6 SCCs) were tested by immunohistochemistry and evaluated semi quantitatively to assess the percentage of positive cells.
Results:
None of the sarcoids presented PD-L1 expression. Regarding SCC, 2 tumors presented <10% of labeled cells; 2 tumors presented 10%-25% of labeled cells and 2 tumors presented 25%-50% of labeled cells. There were statistically significant differences between sarcoids and SCC regarding the expression of PD-L1.
Conclusion:
Our results point to the fact that PD-L1 could be a potential therapeutic target against SCC, and also encourage in-depth studies in this area, with larger sample sizes.
