Salk Scientists Expand Ability of Stem Cells to Regrow Any Tissue Type (image) Salk Institute Share Print E-Mail Caption Human EPS cells (green) can be detected in both the embryonic part (left) and extra-embryonic parts (placenta and yolk sac, right) of a mouse embryo. Credit Salk Institute Usage Restrictions with credit and related coverage. 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.