Loss of a Barrier to Tumor Formation (image) Ecole Polytechnique Fédérale de Lausanne Share Print E-Mail Caption Loss of a barrier to tumor formation: On the left, a protective barrier of activin B expression (red color) is present in normal pancreatic islets. On the right, this barrier is missing in derivative islet tumors. The cyan color shows cell nuclei. Credit Iacovos Michael/EPFL Usage Restrictions Media purposes only. Commercial usage restricted; by permission 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.