UC San Diego

Most breast cancer-related deaths are due to distant metastasis that occur years after successful tumor removal and treatment. Tumor metastasis is a multi-step process in which primary tumors lose cell polarity and undergo dissemination by Epithelial-Mesenchymal Transition (EMT). The disseminated tumor cells circulate throughout the body and often remain in a dormant state after reaching distant organs. Once the microenvironment becomes suitable, the cells undergo Mesenchymal-Epithelial Transition (MET) and exit dormancy, which results in macrometastases. Previous studies show that a transcription factor Twist1 plays a key role in inducing EMT and promoting tumor metastasis. However, the molecular mechanisms of metastasis are not well understood due to the lack of an in vivo mouse model that can monitor disseminated tumor cells. Therefore, we established a Twist1-inducible breast cancer mouse model that utilizes fluorescent markers to visualize and characterize disseminated tumor cells at various stages of metastasis.