When studying human cells in a laboratory, it is important that the media, or the broth that bathes the cells, contains all of the nutrients necessary to support cells through their normal growth and division phases even though they are outside of the body. Bioscientists at Berkeley Lab have a long history of studying breast cancer, and Martha Stampfer, senior scientist in the Biological Systems & Engineering (BSE) Division, has spent decades developing media now widely used by the community. Today, PLOS ONE published a study describing a comprehensive analysis of three kinds of media used to grow human mammary epithelial cells (HMEC).