Over the past few years, imaging technologies and experiments have helped to visualize the dynamics of cellular movements, the signaling pathways, and the nature of tumor-stroma interactions involved in the various stages of the metastatic process. Thus, insights from live imaging could ultimately shed light on how to effectively treat cancer metastasis. The non-receptor tyrosine kinase Pyk2 is highly expressed in invasive cancers, but the mechanism through which it regulates invasion and metastasis are currently unknown. Using in vivo mice models and high-resolution intravital imaging, the project described herein aims to explore the cellular mechanisms by which Pyk2 controls breast tumor cell dissemination from the primary tumor and spreading to distant sites throughout the body. We hope to translate the results from the proposed study into novel strategies for predicting the invasive potential of breast carcinoma and, more importantly, for blocking breast cancer metastasis.