Experimental orthotopic breast cancer as a model for investigation of mechanisms in malignancy and metastasis to the lymph nodes

To understand the fundamental mechanisms behind malignancy of breast tumors and also contribute to the discovery of improved methods for prevention, diagnosis and treatment, animal cancer models remain essential. We aimed to establish an optimal orthotopic cancer model for breast cancer in the immunocompetent Swiss mouse, describing the detailed microanatomy of the mammary glands, the sentinel lymph node and lymphatic mapping, evaluating histopathological changes and characterizing the tumor by computed microtomography and interleukins expression. The inoculation of fresh Ehrlich tumor cells led to a detectable tumor as early as 24 hours later; after 7 days, mammary, muscular, dermal vascular and lymphatic invasion were observed and also micrometastases in mammary adipose tissue, sentinel lymph node and contralateral lymph node.