MSI1 and minimally invasive lung adenocarcinoma: Msi1 protein expression in lung cancer tissue microarray samples. Msi1 expression was analyzed by IHC. Ad, adenocarcinoma; BAC, bronchioloalveolar carcinoma; Ad-Sq, adenosquamous carcinoma; Sq, squamous cell carcinoma; LCLC, large cell lung carcinoma; SCLC, small cell lung carcinoma; Other, mucoepidermoid carcinoma or malignant mesothelioma. * χ2 test