Exploring the association of intratumoral immune cell infiltrates with histopathologic grade in canine mast cell tumors

Authors

Victoria R. Costa, Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA.
Aimee M. Soileau, Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA.
Chin-Chi Liu, Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA.
Cambri E. Moeller, Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA.
Mariano Carossino, Louisiana State University, Department of Pathobiological Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA; Louisiana State University, Louisiana Animal Disease Diagnostic Laboratory (LADDL), River Rd, #1043, Baton Rouge, LA 70803, USA.
Ingeborg M. Langohr, Louisiana State University, Department of Pathobiological Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA; Louisiana State University, Louisiana Animal Disease Diagnostic Laboratory (LADDL), River Rd, #1043, Baton Rouge, LA 70803, USA.
Sita S. Withers, Louisiana State University, School of Veterinary Medicine, Department of Veterinary Clinical Sciences, 1909 Skip Bertman Dr., Baton Rouge, LA 70803, USA. Electronic address: withers1@lsu.edu.

Document Type

Article

Publication Date

10-1-2022

Abstract

Cutaneous canine mast cell tumors (ccMCTs) vary in their biological behavior, treatment, and prognosis, based on their grade. Immune cell infiltration has been associated with prognosis and response to treatments in some human cancers, and immune-targeting therapeutics are increasingly being explored in veterinary oncology. However, currently little is known about the tumor microenvironment (TME) in ccMCTs. Therefore, the objective of this study was to determine the prevalence of T lymphocytes, T regulatory lymphocytes, PD-1+ cells and macrophages in low- and high-grade ccMCTs. Thirty low-grade and 20 high-grade formalin-fixed paraffin-embedded ccMCT samples were included. Immunohistochemistry (IHC) was performed to detect CD3, FOXP3, Iba1, and PD-1 on sequential sections. Three 400x fields with the highest numbers of CD3+ cells were identified for each tumor. The percentage of CD3+, FOXP3+, and Iba1+ cells, and the number of PD-1+ cells, was quantified in each of these three "hot-spot" fields using ImageJ software. Iba1 expression was significantly greater in high-grade compared to low-grade ccMCTs (mean = 12.5% vs. 9.6%, p = 0.043). PD-1 expression was low overall, but a significantly higher number of PD-1-expressing cells was observed in high-grade ccMCTs (median 1 vs. 0, p = 0.001). No significant difference was noted in CD3 and FOXP3 expression between ccMCT grades. Macrophages and PD-1+ cells were more frequent in high-grade, compared to low-grade ccMCTs. Further studies are needed to define the role of macrophages and rare PD-1+ cells in high-grade ccMCTs.

Publication Source (Journal or Book title)

Research in veterinary science

First Page

83

Last Page

91

Recommended Citation

Costa, V. R., Soileau, A. M., Liu, C., Moeller, C. E., Carossino, M., Langohr, I. M., & Withers, S. S. (2022). Exploring the association of intratumoral immune cell infiltrates with histopathologic grade in canine mast cell tumors. Research in veterinary science, 147, 83-91. https://doi.org/10.1016/j.rvsc.2022.04.005