As reported previously and illustrated in Figure 1A, CD2‐MYC/CD2‐Runx2 mice develop rapid onset thymic lymphoma with complete penetrance whereas the parental CD2‐Runx2 and CD2‐MYC strains display low lifetime rates of tumor development.6 To explore further the mechanism of this potent oncogene collaboration, we analyzed early transcriptome changes in the thymus of 10‐day‐old CD2‐Runx2/CD2‐MYC mice. The gene discussed is RUNX2; the disease is thymus lymphoma.