{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T22:32:10Z","timestamp":1775082730611,"version":"3.50.1"},"reference-count":74,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,22]],"date-time":"2023-12-22T00:00:00Z","timestamp":1703203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Portuguese Foundation for Science and Technology (FCT)","award":["UIDP\/00772\/2020"],"award-info":[{"award-number":["UIDP\/00772\/2020"]}]},{"name":"Portuguese Foundation for Science and Technology (FCT)","award":["LA\/P\/0059\/2020"],"award-info":[{"award-number":["LA\/P\/0059\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Currently available treatments for equine melanocytic tumors have limitations, mainly due to mass localization and dimension, or the presence of metastases. Therefore, a search for new therapies is necessary. Programmed cell death-ligand 1 (PD-L1) is expressed by several tumors, blocking T cell-mediated elimination of the tumor cells by binding to programmed cell death protein 1 (PD-1). A novel therapeutic approach using PD-1\/PD-L1 blockade in human melanoma resulted in tumor regression and prolonged tumor-free survival. This study aimed to evaluate the immunohistochemical expression of PD-L1 in equine melanocytic tumors. A total of 77 melanocytic tumors were classified as benign or malignant and evaluated by extension of labeling. A total of 59.7% of the tumors showed &gt;50% of immunolabeled cells. Regarding malignant tumors, 24\/38 tumors presented &gt;50% of labeled cells, 13 tumors presented between 25\u201350% and one tumor presented &lt;10%. Regarding benign tumors, 22\/39 tumors presented &gt;50% of labeled cells, nine tumors presented 25\u201350%, three tumors presented 10\u201325%, two tumors presented &lt;10% and three tumors did not present expression. Our results suggest that PD-L1 blockade may be a potential target for immunotherapy in equine melanocytic tumors and that future clinical research trials into the clinical efficacy of the anti-PD-L1 antibody are necessary.<\/jats:p>","DOI":"10.3390\/ani14010048","type":"journal-article","created":{"date-parts":[[2023,12,22]],"date-time":"2023-12-22T04:44:40Z","timestamp":1703220280000},"page":"48","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Programmed Cell Death-Ligand 1 (PD-L1) Immunohistochemical Expression in Equine Melanocytic Tumors"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7328-2123","authenticated-orcid":false,"given":"Jos\u00e9","family":"Pimenta","sequence":"first","affiliation":[{"name":"CECAV\u2014Veterinary and Animal Research Center, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"},{"name":"CIVG\u2014Vasco da Gama Research Center, EUVG\u2014Vasco da Gama University School, 3020-210 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3902-5374","authenticated-orcid":false,"given":"Justina","family":"Prada","sequence":"additional","affiliation":[{"name":"CECAV\u2014Veterinary and Animal Research Center, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"},{"name":"Veterinary Sciences Department, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6330-4560","authenticated-orcid":false,"given":"Isabel","family":"Pires","sequence":"additional","affiliation":[{"name":"CECAV\u2014Veterinary and Animal Research Center, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"},{"name":"Veterinary Sciences Department, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6336-6515","authenticated-orcid":false,"given":"M\u00e1rio","family":"Cotovio","sequence":"additional","affiliation":[{"name":"CECAV\u2014Veterinary and Animal Research Center, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal"},{"name":"Faculty of Veterinary Medicine, Lus\u00f3fona University, Campo Grande 376, 1749-024 Lisbon, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1016\/j.cveq.2013.08.008","article-title":"Equine Melanocytic Tumors","volume":"29","author":"Phillips","year":"2013","journal-title":"Vet. 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