Assessment of the Accuracy of Immune Deconvolution Methods Applied to Tumor Stroma in Canine Mammary Carcinomas

• Grant number: 25/27727-5
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: April 01, 2026
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Ricardo de Francisco Strefezzi
• Grantee: Débora Peccin do Nascimento
• Supervisor: Enni Markkanen
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Institution abroad: University of Zurich (UZH), Switzerland
• Associated to the scholarship: 24/13310-2 - Quantification of infiltrating T lymphocytes in mammary carcinomas of bitches and their relationship with prognosis, BP.IC

Abstract

Mammary tumors are the most common neoplasms in female dogs and show strong biological similarity to human breast cancer, particularly regarding the role of tumor stroma in disease progression. Among stromal components, T lymphocytes play a central role in modulating the immune response and influencing tumor behavior. CD8+ T cells act in the destruction of neoplastic cells, contributing to a better prognosis, whereas regulatory T lymphocytes suppress antitumor responses and promote tumor progression and immune evasion. Due to their opposing role, detailed analysis of these T cell subtypes and their distribution in tumors is highly relevant for prognosis. Although techniques such as laser capture microdissection (LCM) and RNA sequencing allow high-precision analysis of the stroma patient tissue, it remains unclear how the accuracy of currently available immune deconvolution methods perform when applied to stroma isolated from canine mammary carcinomas. This Research Internship Abroad Project (BEPE-IC) aims to assess the accuracy of immune deconvolution methods, when applied to cancer-associated stroma in canine mammary carcinomas. For this purpose, RNAseq data from stroma previously isolated by laser microdissection will be used and compared with the actual quantification of CD8+ and regulatory T lymphocytes obtained by immunohistochemistry from the same samples. Validation between the in-silico data and the histological findings will determine the reliability of these approaches in characterizing the tumor microenvironment and thereby unlock the full potential of existing datasets contributing to advances in comparative oncology and to a better understanding of immune infiltration in mammary tumors of female dogs.