by Simone Alves
Chromosome instability is a problem for long-term culture of human embryonic stem cells
Long-term culture of human embryonic stem (hES) cells can cause them to gain or lose large sections of chromosomes, report two papers in Nature Biotechnology. This instability can lessen the reproducibility and reliability of experimental results, and, by raising the specter of cancer, could hinder the clinical application of stem cells.
Checking cell lines in practice is not always easy, experimentally or logistically, says Anselme Perrier of The Institute for Stem Cell Therapy in Evry, France. He and his colleagues discovered that long-term culture of five hES cell lines resulted in a genomic amplification of the 20q.11.21 locus in four cases. "We discovered this mutation during routine quality control" says Perrier, "and it was happening too frequently for it to simply be an artefact".