SnapShot: Caspases

(Cell 146, 633–644; August 19, 2011) In theDiscussionof theabovearticle,weneglected tociteChaffer et al. (2011),who recently identifiedplasticity in cancercell populations inwhich non-stemcancer cells cangive rise to cancer stem-like cells. Their findings, togetherwithour analysesof breast cancer cell lines and their ability to regenerate equilibrium populations of stem and non-stem cells, establish the ability of non-stem cells to convert into stem cells in tumorigenesis. The reference appears below and is included with a corrected version of the article now available online. Chaffer,C.L., Brueckmann, I., Scheel, C., Kaestli, A.J.,Wiggins, P.A., Rodrigues, L.O., Brooks,M.,Reinhardt, F., Su,Y., Polyak,K., et al. (2011). Normal and neoplastic nonstem cells can spontaneously convert to a stem-like state. Proc. Natl. Acad. Sci. 108, 7950–7955.