Lung adenocarcinomas are a heterogeneous set of diseases with distinct genetic and histologic characteristics. Besides the discovery of oncogenic mutations and introduction of the histologic classifications (2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society and 2015 WHO), increasing evidence has linked this intertumor heterogeneity to the lung lineage–specific pathways and lineage genes. Therefore, in this study, we assessed the gene expression of identified lung lineage genes to study their role in distinguishing lung adenocarcinoma diversities.