Figure 1.

Current paradigm of lung adenocarcinoma. The majority of lung adenocarcinomas develop through a multi-step tumorigenesis pathway. Tumors develop from atypical adenomatous hyperplasia (AAH) to bronchioalveolar carcinoma (BAC), and ultimately progress to multiple types of invasive tumors. Mouse lung adenoma is equivalent to human AAH and BAC. RUNX3 is inactivated in most early AAH (human) and early adenoma (mouse). K-Ras activation is detected in relatively late AAH or adenoma.^{21, 48}