Programmed Cell Death Ligand 1 Expression in Canine Cancer.
BACKGROUND
Antibody therapy targeting programmed cell death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) is a promising therapy in human cancer, but only limited information on PD-L1 expression in canine tumors is available.


METHODS
PD-L1 expression was examined in 31 canine tumor cell lines of various origins by flow cytometry and western blotting, and in canine tumor and normal tissue specimens by immunohistochemistry.


RESULTS
PD-L1 was only expressed on the cell surface of a small number of cell lines but was found expressed within the cells of almost all cell lines. Immunohistochemistry revealed that PD-L1 is frequently expressed in malignant melanoma, mammary gland tumor, mast cell tumor and lymphoma, but less frequently in soft-tissue sarcoma and hemangiosarcoma. PD-L1 was also expressed in some of the cells of normal canine tissue specimens.


CONCLUSIONS
Canine tumors with PD-L1 expression that were identified in this study are potential candidates for antiPD-1 and antiPD-L1 therapy.
Laboratory of Molecular Diagnostics and Therapeutics, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Kazuha
K
Shosu
Laboratory of Veterinary Pathology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Masashi
M
Sakurai
Laboratory of Molecular Diagnostics and Therapeutics, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Kumi
K
Inoue
Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Takayuki
T
Nakagawa
Laboratory of Veterinary Pathology, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.
Hiroki
H
Sakai
Laboratory of Veterinary Pathology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Masahiro
M
Morimoto
Laboratory of Veterinary Internal Medicine, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan Biomedical Science Center for Translational Research, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Masaru
M
Okuda
Laboratory of Molecular Diagnostics and Therapeutics, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan Biomedical Science Center for Translational Research, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi, Japan.
Shunsuke
S
Noguchi
Laboratory of Molecular Diagnostics and Therapeutics, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan Biomedical Science Center for Translational Research, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi, Japan mizutaku@yamaguchi-u.ac.jp.
Takuya
T
Mizuno
D000818:Animals; D060890:B7-H1 Antigen / Q000096:biosynthesis*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D004283:Dog Diseases / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D005434:Flow Cytometry; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D008223:Lymphoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D015674:Mammary Neoplasms, Animal / Q000378:metabolism / Q000473:pathology; D034801:Mastocytoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D008545:Melanoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D061026:Programmed Cell Death 1 Receptor / Q000096:biosynthesis*
D060890:B7-H1 Antigen; D061026:Programmed Cell Death 1 Receptor
Canine cancer; PD-L1; immunohistochemistry; programmed cell death ligand 1