Neutrophils (IMAGE) Penn State Caption Neutrophils, stained brown, are visible in a human glioblastoma tissue sample, where tumor cells are stained in blue. Credit Penn State College of Medicine 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.