Circulating tumor cells (CTCs) are rare cells that originate from a malignancy and circulate freely in the peripheral blood. The ability to capture and study CTCs is an emerging field with implications for early detection, diagnosis, determining prognosis and monitoring of cancer, as well as for understanding the fundamental biology of the process of metastasis. Here, we review the development and initial clinical studies with a novel microfluidic platform for isolating these cells, the CTC-chip, and discuss its potential uses in the study of lung cancer.