In the article on the advantages of GEMs over xenografts in the April 1, 2006 issue of Cancer Research (1), references 14 and 15 were incorrect. The corrected references are:

14. Daley GQ, Van Etten RA, Baltimore D. Induction of chronic myelogenous leukemia in mice by the P210 bcr/abl gene of the Philadelphia chromosome. Science 1990;247:824–30.

15. Wolff NC, Ilaria RL, Jr. Establishment of a murine model for therapy-treated chronic myelogenous leukemia using the tyrosine kinase inhibitor STI571. Blood 2001;98:2808–16.

Becher OJ, Holland EC. Genetically engineered models have advantages over xenografts for preclinical studies.
Cancer Res