Where is Tn-MUC1 in a Cell (VIDEO) University of Pennsylvania School of Medicine This video is under embargo. Please login to access this video. Caption 1. Confocal microscopy of normal human kidney Immunostained for cell surface protein EpCAM (red) and normal MUC1. Normal MUC1 is found at the cellular surface in human kidney. 2. Normal human kidney immunostained for EpCAM and Tn-MUC1 (green). Tn-MUC1 is found intracellular in normal MUC1-expressing tissues. 3. Human breast cancer immunostained for EpCAM and Tn-MUC1. Tn-MUC1 is found at the cell membrane in cancer. Credit Avery Posey, Ph.D., Perelman School of Medicine, University of Pennsylvania 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.