Identification of serum exosomal lncRNA MIAT as a novel diagnostic and prognostic biomarker for gastric cancer

BACKGROUND: Accumulating evidence has demonstrated that long non‐coding RNAs (lncRNAs) MIAT is significantly upregulated in many cancer types including gastric cancer (GC). However, the potential clinical significance of serum exosomal MIAT in GC is unknown. METHODS: In this study, a total of 109 GC patients, 48 gastric adenoma patients, and 50 healthy individuals were recruited. Serum exosomal MIAT levels were detected in all participants using quantitative real‐time reverse transcription‐polymerase chain reaction (qRT‐PCR). RESULTS: The exosomes we extracted from the serum samples were positive for TSG101, CD63, and Flotillin‐1, which were known exosome markers. Serum exosomal MIAT levels were significantly higher in GC patients than in gastric adenoma patients and healthy controls. Interestingly, gastric adenoma patients with higher serum exosomal MIAT expression were more prone to develop GC. In addition, serum exosomal MIAT levels were significantly decreased in post‐treatment blood samples compared to pre‐treatment samples, while markedly increased in the cases suffering recurrence. Moreover, serum exosomal MIAT upregulation was significantly associated with worse clinical variables and shorter survival. Furthermore, serum exosomal MIAT was identified as an independent prognostic factor for GC. CONCLUSIONS: Collectively, serum exosomal lncRNA MIAT might serve as a promising novel biomarker for monitoring the progression of GC.