PD-1, PD-L1, and PD-L2 Expression as Predictive Markers in Rare Feline Mammary Tumors

Feline mammary carcinoma (FMC) exhibits aggressive behavior, with limited treatment options. Given the relevance of the PD-1/PD-L1/PD-L2 axis in human breast cancer immunotherapy, this study assessed PD-1 and its ligands in rare FMC histotypes (n = 48) using immunohistochemistry on tumor cells (TCs), intratumoral lymphocytes (iTILs), and stromal tumor-infiltrating lymphocytes (sTILs). PD-1 was expressed in 13% of TCs, 85% of iTILs, and 94% of sTILs, while PD-L1 was observed in 46% of TCs, 96% of iTILs, and 100% of sTILs. PD-L2 was expressed in 79% of TCs and 100% of both iTILs and sTILs, with PD-L1/PD-L2 co-expression in 42% of TCs. Higher PD-1 IHC scores in TCs were associated with a less aggressive biological behavior; PD-L1 in iTILs was linked to skin ulceration, whereas PD-L2 in TCs was associated with its absence. Our findings highlight the relevance of the PD-1/PD-L1/PD-L2 immune checkpoint in rare FMC subtypes and support further investigation into checkpoint-blockade therapies.

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Publication Details

Journal
Veterinary Sciences
Published
2025-08-03
DOI
https://doi.org/10.3390/vetsci12080731
Citations
1
Primary Topic
Cancer Immunotherapy and Biomarkers
Type
article
Field-Weighted Citation Impact
1.05
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article

PD-1, PD-L1, and PD-L2 Expression as Predictive Markers in Rare Feline Mammary Tumors

Adelina Gama, Pedro Faísca, Hugo Vilhena, Jorge Correia et al.
1 citations
Veterinary Sciences
Cancer Immunotherapy and Biomarkers
1.05
article

PD-1, PD-L1, and PD-L2 Expression as Predictive Markers in Rare Feline Mammary Tumors

Adelina Gama, Pedro Faísca, Hugo Vilhena, Jorge Correia, Anabela Alves, Andreia Santos, Fernanda Seixas, Patrícia Dias‐Pereira, M.A. Pires, Fernando Ferreira, Carla Marrinhas, Maria do Carmo Franco, Joana Santos
article en
1 citations

Abstract

Feline mammary carcinoma (FMC) exhibits aggressive behavior, with limited treatment options. Given the relevance of the PD-1/PD-L1/PD-L2 axis in human breast cancer immunotherapy, this study assessed PD-1 and its ligands in rare FMC histotypes (n = 48) using immunohistochemistry on tumor cells (TCs), intratumoral lymphocytes (iTILs), and stromal tumor-infiltrating lymphocytes (sTILs). PD-1 was expressed in 13% of TCs, 85% of iTILs, and 94% of sTILs, while PD-L1 was observed in 46% of TCs, 96% of iTILs, and 100% of sTILs. PD-L2 was expressed in 79% of TCs and 100% of both iTILs and sTILs, with PD-L1/PD-L2 co-expression in 42% of TCs. Higher PD-1 IHC scores in TCs were associated with a less aggressive biological behavior; PD-L1 in iTILs was linked to skin ulceration, whereas PD-L2 in TCs was associated with its absence. Our findings highlight the relevance of the PD-1/PD-L1/PD-L2 immune checkpoint in rare FMC subtypes and support further investigation into checkpoint-blockade therapies.

Veterinary SciencesVol. 12(8)
University of Lisbon (PT), University of Trás-os-Montes and Alto Douro (PT), Universidade do Porto (PT), Universidade Politécnica de Lisboa (PT), Escola Universitária Vasco da Gama (PT), Institute of Agrifood Research and Technology (ES), Rede de Química e Tecnologia (PT), Centro Hospitalar do Baixo Vouga (PT), Universidade Lusófona (PT)
Openalex Percentile: Top 19%
Cancer Immunotherapy and Biomarkers
1.05
DOIOpen Access PDFOpenAlex
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