Ever since biologists learned how to grow human cells in culture half a century ago, the cells have been plagued by a problem of identity: many commonly used cell lines are not actually what researchers think they are. Cell-line misidentification has led to mistakes in the literature, misguided research based on those results and millions wasted in grant money. But a universal system for determining the identity of cell lines may now be in view. Next month, a nonprofit biological repository based in Virginia that stores 3,600 cell lines from more than 150 species, plans to unveil standardized protocols for verifying the identity of cultured cells using DNA fingerprinting. Labs worldwide would use the protocols to determine whether a breast-cancer line, for instance, did come from breast tissue. The group also plans to create a public database to store DNA profiles of validated lines, allowing researchers to compare their own cell cultures with the reference lines. “I really think it’s fantastic progress,” says Rolf König, director of UTMB’s Tissue Culture Core Facility.