Neighboring enhancer of FOXA2 (NEF) is a newly discovered long non‑coding RNA (lncRNA) that serves an oncogenic function in the metastasis of hepatocellular carcinoma, while its involvement in other types of cancer and in tumor cell proliferation remain unknown. In the present study, tumor tissues and adjacent healthy tissues were obtained from patients with gastric carcinoma, and blood was extracted from patients with gastric carcinoma and healthy controls. Expression of NEF in those tissues was detected using a reverse transcription‑quantitative polymerase chain reaction. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic value of serum lncRNA NEF for gastric carcinoma. All patients were followed‑up for 5 years following discharge, and survival curves were plotted to evaluate the diagnostic value of serum lncRNA‑NEF for gastric carcinoma. LncRNA‑NEF overexpression and small interfering RNA (siRNA) silencing cell lines were established and the effects on cell proliferation and runt‑related transcription factor 1 (Runx1) expression were detected using a Cell Counting Kit‑8 assay and western blot analysis, respectively. It was revealed that NEF was significantly downregulated in tumor tissues compared with in adjacent tissues. Levels of circulation NEF in serum were lower in patients with gastric carcinoma compared with in healthy controls, and were decreased with the increasing stages of primary tumor. Serum NEF is a sensitive diagnostic and prognostic marker for gastric carcinoma. NEF siRNA silencing promoted, and overexpression inhibited, gastric carcinoma proliferation. In addition, NEF overexpression promoted, and NEF siRNA silencing inhibited, Runx1 expression. Therefore, it was concluded that lncRNA NEF may participate in the regulation of cancer cell proliferation by regulating Runx1 expression.