Abstract
In the search for biomarkers of metastasis, attention has been largely placed on ensemble-averaged measurements that screen for molecules or genes. However, individual molecular changes do not always result in disease, and population-based measurements can mask the molecular signatures of the cells responsible for disease. Here, we describe a device that selects for cells based on chemotactic behavior rather than based on molecular differences, enabling the most aggressive cells to be studied independently from the heterogeneous population.