Malignant Tissue (image) Harvard University Caption Mammary epithelial tissue structures undergo characteristic changes as tumors progress from benign to invasive. These human breast cancer tissue samples illustrate the difference. The scale bar is 50 microns. Credit Image courtesy of Ovijit Chaudhuri, Harvard University. Usage Restrictions Editorial use only. 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.