Scientists say they have transformed one type of cell into another in mice, a step toward the growing of replacement tissues to treat diseases.

The cell identity switch turned ordinary pancreas cells into the rarer type that churns out insulin, essential for preventing diabetes. The report was published online Wednesday by the journal Nature.

Douglas Melton, co-director of the Harvard Stem Cell Institute and a researcher with the Howard Hughes Medical Institute, cautioned that the approach is not ready for use in humans.