Feline Mammary Carcinoma as a Comparative Model of Human Breast Cancer: An Integrative Review

Background: Feline mammary carcinoma (FMC) is an aggressive neoplasm in cats and has attracted interest in comparative oncology because selected clinicopathological and molecular features overlap with human breast cancer. Methods: This integrative review synthesized literature was identified in PubMed/MEDLINE, Scopus, and Web of Science from database inception to 30 March 2026, focusing on epidemiology, pathology, biomarkers, tumor microenvironment, omics, therapy, and comparative oncology. Feline-derived evidence was distinguished from the human breast cancer literature, and findings were synthesized qualitatively because of substantial methodological and clinical heterogeneity. Results: FMC shows recurrent associations with aggressive histological features, hormone receptor-negative phenotypes, HER2-related signaling, immune checkpoint pathways, and emerging molecular and liquid-biopsy biomarkers. However, differences in molecular classification, methodology, treatment, cohort size, and clinical validation limit direct cross-species inference. Conclusions: FMC may serve as a complementary, question-specific comparative oncology system for studying selected aspects of aggressive mammary tumor biology, metastasis, tumor–host interactions, biomarkers, and therapeutic response. Its translational relevance remains hypothesis-generating and requires standardized methods and independent clinical validation.