Cancerous Tumor Tissue under a Microscope (IMAGE) Weizmann Institute of Science Caption Cancerous tumor tissue under a microscope: T cells grown under low oxygen conditions (green) and regular T cells (purple) show similar distribution patterns vis-à-vis blood vessels (red). Right: The content of granzyme B, a cell-killing enzyme (red), is much higher in T cells grown under low oxygen conditions (top) than in regular T cells (bottom). Credit Weizmann Institute of Science 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.