CTC Cluster Unfolds to Pass Through Capillary-Sized Constriction (video) Massachusetts General Hospital Share Print E-Mail Loading video... Caption Cells within a prostate cancer circulating tumor cell cluster unfold to pass through a capillary-sized constriction in a single-file chain. Credit Center for Engineering in Medicine, Massachusetts General Hospital Usage Restrictions Restricted to coverage of this research study only. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.