Overexpression of FNDC1 in Gastric Cancer and its Prognostic Significance

Objectives: The aims of this study were to compare the expression of fibronectin type III domain containing 1 (FNDC1) in gastric cancer (GC) and normal gastric tissue, to explore the prognostic significance of FNDC1 expression in patients with gastric adenocarcinoma, and to analyze FNDC1-related signaling pathways. Methods: The expression level of FNDC1 was initially predicted using the Oncomine and Cancer Genome Atlas databases. A Kaplan-Meier plotter database was mined to examine the clinical prognostic significance of FNDC1 mRNA in patients with GC. Subsequently, immunohistochemistry was used to measure FNDC1 protein expression levels in tissue from 90 cases of GC and paired adjacent normal tissue. Kaplan-Meier univariate and Cox multivariate survival analyses were used to determine the prognostic role of FNDC1 expression. Results: Bioinformatic data indicated that FNDC1 mRNA expression levels were significantly highly expressed in GC compared with normal gastric tissue (all P < 0.05), and patients with GC with high FNDC1 mRNA expression levels had remarkably lower overall survival (all P < 0.01). Immunohistochemical results revealed that expression levels of FNDC1 protein were significantly increased in GC compared with normal gastric tissue (P < 0.001). Additionally, Kaplan-Meier univariate and Cox multivariate survival analyses indicated that increased expression of FNDC1 was an independent predictor of poor prognosis in patients with GC (all P < 0.05). Conclusions: FNDC1 was highly expressed in GC, and high expression of FNDC1 was an independent predictor of poor prognosis in patients with GC. FNDC1 co-expressed genes were largely enriched in extracellular matrix-receptor interactions, which are closely related to tumor metastasis.