Based upon the reports that GGOs manifested on thin-section CT have been found to be associated with certain histopathological types, such as atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS, previously known as bronchioloalveolar carcinoma (BAC)), and minimally invasive adenocarcinoma (MIA, previously known as adenocarcinoma with a predominant BAC component (ABAC)) [22], and that EGFR mutation is frequently detected in these pathological subtypes, we sought to study whether the detection of GGO on CT correlates with EGFR mutation. This evidence concerns the gene EGFR and adenocarcinoma in situ.