In contrast to lungs of SpC-c-MYC single transgenic mice that only develop premalignant lesions, tumor nodules in lungs of compound or late SpC-c-MYC single transgenic mice were rapidly expanding and frequently contained macroscopic tumors with columnar cells that were absent in SpC-C-RAF BxB–driven adenomas (Figure 1C). Here, MYC is linked to adenoma.