My work, primarily focusing on tumor progression and metastasis, has changed many research paradigms in the field, as this complex process is responsible for the majority of cancer deaths. Once cancer has spread, current treatments ultimately fail for most patients. Furthermore, metastasis can be particularly insidious, as it may develop after variable and unpredictable periods of tumor dormancy. My research program strives for a better understanding of metastasis and thus has the potential to improve cancer patient survival and quality of life. First, I have a major program aimed at understanding the biology of the cancer progression and metastatic process. Second, I have a major program focused on the secreted, integrin-binding protein osteopontin (OPN) and its target gene Ran GTPase (Ran). I have shown that Ran contributes functionally to the malignant behavior of cancer cells and that measuring Ran levels in patients may provide clinically useful information.