Metastasis and primary tumor growth can be initiated simultaneously. Oncogenes and tumor suppressors alter mechanisms linked to cell movement and cell survival, before causing frank tumor growth. And a paradigm shift becomes apparent: metastases do not necessarily originate from small subpopulations of cells present in large invasive tumors. In this interview keynote speaker Prof. Julio Aguierre-Ghiso, Icahn School of Medicine at Mount Sinai, New York (USA) summarizes the clinical impact of new insights into metastasis formation.