Endothelial cells (IMAGE) University of North Carolina Health Care Caption Control cells and endothelial cells expressing PIK3CA-activating mutations cultured in 3D fibrin matrices and imaged at 0 and 168 hours after seeding. Scale bars, 1000 μm. Credit Aw et al. Usage Restrictions Credit must be given to the creator. License CC BY 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.