Formalin-fixed paraffin-embedded sections of lung tissue from 31 patients diagnosed with pulmonary adenocarcinoma, including 4 non-invasive adenocarcinomas (2 atypical adenomatous hyperplasia (AAH), 2 adenocarcinoma in situ (AIS)), 11 minimally invasive adenocarcinomas (MIA), and 16 invasive lesions of different histological subtypes, were stained with antibodies against MMP-13 (Fig 6). The gene discussed is MMP13; the disease is adenocarcinoma in situ.