CDKN2A and neoplasm: In contrast to the Eμ-myc p53-/- tumors, the Eμ-myc Arf-/- seemed to be more dense in the peripheral regions (p = 0.002 on one end (Section S1) and p = 0.009 on the other end (Section S5)), whereas they were about the same for both tumor types in the intermediate sections S2 and S4.