Nature 441, 1097–1099 (2006) It has been drawn to our attention (by J. Lakota, and by J. J. Minguell and G. P. Lasala) that we used the abbreviation for bone-marrow-derived stem cells (BMSCs) inappropriately in some parts of our Insight Progress article. BMSC is a commonly used acronym for the heterogeneous adult stem cells in bone marrow.