Cells pulse together as they grow—and malignant cells pulse the longest

Epithelial cells are the tiny shields that line and protect our bodies. In a developing embryo, epithelial cells grow, divide and move into positions to form the outer layers of our skin and the surfaces of our organs and blood vessels. When we scrape our skin, suffer an internal tear or undergo surgery, epithelial cells migrate to the site of injury to heal a wound. And when epithelial cells go haywire, they can turn malignant and spread through the body as cancer.