title: Molecular based subtyping of feline mammary carcinomas and clinicopathological characterization.
abstract: Molecular classification of feline mammary carcinomas (FMC) from which specific behavioral patterns may be estimated has potential applications in veterinary clinical practice and in comparative oncology. In this perspective, the main goal of this study was to characterize both the clinical and the pathological features of the different molecular phenotypes found in a population of FMC (n = 102), using the broadly accepted IHC-based classification established by St. Gallen International Expert Consensus panel. The luminal B/HER2-negative subtype was the most common (29.4%, 30/102) followed by luminal B/HER2-positive subtype (19.6%, 20/102), triple negative basal-like (16.7%, 17/102), luminal A (14.7%, 15/102), triple negative normal-like (12.7%, 13/102) and finally, HER2-positive subtype (6.9%, 7/102). Luminal A subtype was significantly associated with smaller tumors (p = 0.024) and with well differentiated ones (p < 0.001), contrasting with the triple negative basal-like subtype, that was associated with larger and poorly differentiated tumors (p < 0.001), and with the presence of necrotic areas in the tumoral lesion (p = 0.003). In the survival analysis, cats with Luminal A subtype presented the highest survival time (mean OS = 943.6 days) and animals with triple negative basal-like subtype exhibited the lowest survival time (OS mean = 368.9 days). Moreover, two thirds (64%, 32/50) of the queens with multiple primary tumors showed different molecular subtypes in each carcinoma, revealing that all independent lesions should be analyzed in order to improve the clinical management of animals. Finally, the similarities between the subtypes of feline mammary tumors and human breast cancer, reveal that feline can be a valuable model for comparative studies.
authors.affiliation: CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Soares
authors.affiliation: CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Madeira
authors.affiliation: CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Correia
authors.affiliation: CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Peleteiro
authors.affiliation: Breast Unit, Champalimaud Clinical Center, Lisbon, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Cardoso
authors.affiliation: CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal. Electronic address: fernandof@fmv.ulisboa.pt.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000145:classification*; D002415:Cats; D005260:Female; D015674:Mammary Neoplasms, Animal / Q000737:chemistry / Q000145:classification*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D016019:Survival Analysis
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases
keywords: Cancer model; Feline mammary carcinoma; Immunohistochemistry; Luminal B; Molecular subtype; Triple negative