Tumor Cells (IMAGE) University of Southern California Caption Development of brain metastasis is a complex process in which metastatic cells (green) overcome the protective effect of immune cells (red). Credit Remi Klotz in Yu lab/USC Usage Restrictions None License Licensed content 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.