However, inactivation of most lineage-determining transcription factors does not induce adenoma; the notable exception is Runx3. In mouse lung, inactivation of Runx3 induces adenoma and abrogates oncogene surveillance mechanisms.21 These observations provide an important clue about how adenoma develops and how K-RAS-activated adenoma cells evade cellular defense mechanisms. The gene discussed is KRAS; the disease is adenoma.