Clinicopathological, gene expression and genetic features of stage I lung adenocarcinoma with necrosis

•Tumor necrosis was independently associated with higher risk of recurrence.•The presence of tumor necrosis itself is an important predictive indicator.•The cases with necrosis have distinct clinicopathological and genetically features. The purpose of this study was to investigate the clinicopathological, gene expression and genetic features of stage I lung adenocarcinoma with necrosis. We retrospectively reviewed 521 cases with pathologic stage I lung adenocarcinoma resected by lobectomy and lymph node dissection. We calculated the ratio of tumor necrotic area by digital image analysis and investigated the relationship between tumor necrosis and prognosis. Furthermore, we analyzed the differentially expressed genes between cases with and without necrosis using The Cancer Genome Atlas Lung Adenocarcinoma (TCGA-LUAD) dataset. Using whole exon sequencing data (n = 97), we examined whether tumor necrosis correlates with single nucleotide variants (SNVs) and driver mutations. Eighty four (16%) cases of the study cohort had tumor necrosis. The presence of necrosis significantly correlated with poorer prognosis (5-year overall survival: 91.9% vs. 75.4%, p