An immunocompetent mouse model of metastatic triple-negative breast cancer

Breast cancer (BC) represents a major socio-economic challenge worldwide due to its high morbidity and mortality rates. Despite various therapeutic strategies, the heterogeneity of breast cancer and the resistance of tumour cells often lead to treatment failure. Consequently, the use of animal models of BC is crucial for understanding the cellular and molecular mechanisms involved in the different stages of carcinogenesis and for screening new drugs to assess their efficacy, potential safety and side effects. The accuracy, advantages and limitations of these models are the subject of ongoing debate among researchers, as no single model is standardised for all types of BC due to their unique genetic and phenotypic characteristics and the diversity of responses to treatment. This chapter focuses on the use of xenograft animal models by directly transplanting tumour cells into the BC microenvironment. It encompasses cell and animal preparation procedures, as well as transplantation methods. This technique provides a model of stage IV triple-negative BC in immune-competent animals, characterised by a short, non-surgical induction period. This model is particularly valuable for the study of carcinoma in situ and metastasis.