Massachusetts General Hospital investigators have developed a microchip-based device that can isolate, enumerate and analyze circulating tumor cells (CTCs, which are one in a billion cells) from a blood sample.

Because of their rarity and fragility, it has not been possible to get information from CTCs that could help clinical decision-making, but the new device–called the “CTC-chip”–has the potential to be an invaluable tool for monitoring and guiding cancer treatment.