Overexpression of fibronectin type III domain containing 3B is correlated with epithelial-mesenchymal transition and predicts poor prognosis in lung adenocarcinoma

Fibronectin (FN) type III domain containing 3B (FNDC3B), a member of the FN family, regulates the invasion and metastasis of cells in numerous tumor types. However, the mechanisms through which FNDC3B regulates carcinogenesis in lung adenocarcinoma (LADC) tissues have remained elusive. The present study revealed that the protein levels of FNDC3B and vimentin were significantly elevated in LADC tissues compared with those in normal lung tissues. By contrast, the expression of E-cadherin was decreased in LADC tissues compared with that in normal lung tissues. Furthermore, the aberrant expression of FNDC3B and epithelial-mesenchymal transition (EMT) markers was significantly associated with histological differentiation, lymph node metastasis and tumor-nodes-metastasis stage. Kaplan-Meier analysis indicated that a high expression of FNDC3B may be associated with poor overall survival of patients with LADC. In addition, overexpression of FNDC3B promoted the protein expression of EMT-associated genes in the A549 lung adenocarcinoma cell line. In conclusion, the present results support the notion that FNDC3B acts as an oncogene in LADC; it may serve a pivotal role in the development and progression of LADC and may participate in the regulation of the EMT.