Background: Molecular classification of lung adenocarcinoma (LUAD) based on transcriptomic features has been widely studied. The complementarity of data obtained from multilayer molecular biology could help the LUAD classification via combining multi-omics information. Methods:We successfully divided samples from the The Cancer Genome Atlas (TCGA) (n=437) into four subtypes (CS1, CS2, CS3 and CS4) by 10 comprehensive multi-omics clustering methods in the "movics" R package. Meanwhile, external validation sets from different sequencing technologies proved the robustness of the grouping model. The relationship between subtypes, prognosis, molecular features, tumor microenvironment and response to first-line therapy was further analyzed. Next we used univariate Cox regression analysis and Lasso regression analysis to explore the application of biomarkers in clinical prognosis and constructed a prognostic model.Results: CS1 showed the worst overall survival (OS) among all four clusters, possibly related to its poor immune infiltration, higher tumor mutation and worse chromosomal stability. Patients in different subtypes differed significantly in cancer stem cell characteristics, activation of cancer-related pathways, sensitivity to chemotherapy and immunotherapy. The prognostic model showed good predictive performance. The 1-, 2-and 3-year areas under the curve of risk score were 0.779, 0.742 and 0.678, respectively. Seven genes (DKK1, TSPAN7, ID1, DLGAP5, HHIPL2, CD40 and SEMA3C) used to build the model may be potential therapeutic targets for LUAD.Conclusions: Four LUAD subtypes with different molecular characteristics and clinical implications were identified successfully through bioinformatic analysis. Our results may contribute to precision medicine and inform the development of rational clinical strategies for targeted and immune therapies.

Anastomotic leakage is a life-threatening complication for esophageal cancer patients who received McKeown esophagectomy. Cervical drainage tube penetrating anastomosis is a rare but noteworthy cause of long-term nonunion of esophagogastric anastomosis. Here we reported two cases of esophageal cancer patients who received McKeown esophagectomy. The first case acquired the anastomotic leakage on postoperative day (POD) 7, and lasted for 56 days. The cervical drainage tube was removed at POD 38, and the leakage healed in 25 days. The second case acquired the anastomotic leakage on POD 8 and lasted for 95 days. The cervical drainage tube was removed at POD 57, and the leakage healed in 46 days. The two cases demonstrated the duration-prolonging effect of drainage tube penetrating anastomosis, which should not be overlooked in clinical practice. We suggested paying attention to the duration of leakage, the drainage fluids amounts and characteristics, and the imaging manifestations to help diagnose. If the cervical drainage tube penetrated the anastomosis, the tube should be eliminated as soon.