Analyzing the Role of Proteases in Breast Cancer Progression and Metastasis Using Primary Cells from Transgenic Oncomice.

It is becoming increasingly evident that progression and metastasis of solid cancers is driven by the interaction of oncogene-transformed cancer cells and non-malignant host cells in the tumor stroma. In this process, the immune system contributes a complex set of highly important pro- and antitumor effects, which are not readily recapitulated by commonly used xenograft cancer models in immunodeficient mice.Therefore, we provide protocols for isolation of primary tumor cells from the MMTV-PymT mouse model for metastasizing breast cancer and their resubmission to congenic immunocompetent mice by orthotopic transplantation into the mammary gland or different routes of injection to induce organ-specific experimental metastasis, including intravenous, intracardiac, and caudal artery injection of tumor cells. Moreover, we describe protocols for sensitive detection and quantification of the metastatic burden.