Abstract: Objective To explore the expression of fibronectin type III domain containing 1 (FNDC1) protein in lung adenocarcinoma and its prognostic significance. Methods The expression of FNDC1 in lung adenocarcinoma was predicted by analysis of data from GEO database and GEPIA, and the results were verified by immunohistochemical staining in 92 pairs of clinical specimens of lung adenocarcinoma and adjacent tissues. We further analyzed the correlation of FNDC1 expression with the clinicopathological features of the patients, and evaluated its prognostic value using Cox survival analysis. Results Analysis of the data form GEO database and GEPIA showed a significantly higher expression level of FNDC1 in lung adenocarcinoma than in matched normal tissues (P<0.05). Kaplan-Meier survival analysis suggested that a high expression of FNDC1 protein was associated with a significantly shorter overall survival time of the patients (P<0.05). Immunohistochemistry of the clinical specimens also showed a significantly higher protein expression of FNDC1 in lung adenocarcinoma tissues than in paired adjacent tissues (P<0.001). A high expression of FNDC1 protein was significantly correlated with advanced clinical stage, T stage and N stage (P<0.05). Cox univariate and multivariate regression survival analysis indicated that an increased expression of FNDC1 was an independent risk factor for poor prognosis of the patients with lung adenocarcinoma (P<0.05). Conclusion FNDC1 protein is highly expressed in patients with lung adenocarcinoma and in closely related with the occurrence, progression and prognosis of the tumor, suggesting the value of FNDC1 protein as a potential biomarker for assessment of the survival and prognosis of patients with lung adenocarcinoma.

Key words: lung adenocarcinoma; fibronectin type III domain containing 1; bioinformatics；immunohistochemistry; prognosis