Tumor growth of human breast cancer cell lines in Rag2^−/−;Il2rg^−/−, but not in nude mice.

<p>Abbreviations: wk, weeks; SEM, standard error of the mean.</p>a<p>Tumor volumes at 12–13 weeks after cell injection, except 474-EGFP at 23 weeks.</p>b<p>All nude mice were tumor-free 15 weeks after cell injection.