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Multiplexed Immunofluorescence Analysis and Quantification of Intratumoral PD-1+ Tim-3+ CD8+ T Cells
Published on: February 8, 2018
PD-1, PD-L1, and PD-L2 Expression as Predictive Markers in Rare Feline Mammary Tumors
Maria Franco1,2, Fernanda Seixas2,3,4, Maria Dos Anjos Pires2,3,4
1CIISA-Center of Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisboa, Portugal.
None:
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.
