Educating yourself about the origin of your cell lines can guide you toward the right media. This information should be available from either the cells’ vendor or from the literature, if the cells came from another lab. The European Collection of Cell Cultures (ECACC), for which Sigma-Aldrich is a distributor, also can recommend media for particular cell lines. Specialized cell lines—like hybridomas, whose sole purpose is to produce an expressed protein—may require extra support from specially formulated media. “The media become more specialized and customized according to the needs of that particular cell line, and even the particular protein they’re expressing,” says Finley.