Circulating miR-222 in plasma and its potential diagnostic and prognostic value in gastric cancer

Previous studies have revealed the significance of circulating microRNAs as biomarkers for cancers. The aim of this study was to detect the levels of circulating microRNA-222 (miR-222) in plasma of gastric cancer (GC) patients and evaluate its diagnostic and prognostic value. Levels of circulating miR-222 were detected by using qRT-PCR in plasma of 114 GC patients, 36 chronic atrophic gastritis (CAG) patients and 56 healthy controls. The result showed that the expression of circulating miR-222 in plasma was significantly upregulated in GC compared with CAG and healthy controls (all at P < 0.001). And its high level was significantly correlated with clinical stages (P < 0.001) and lymph nodes metastasis (P = 0.009). The receiver operating characteristics (ROC) curve analyses revealed that miR-222 had considerable diagnostic accuracy, yielded an AUC (the areas under the ROC curve) of 0.850 with 66.1 % sensitivity and 88.3 % specificity in discriminating GC from healthy controls. Moreover, Kaplan-Meier analysis demonstrated a correlation between increased circulating miR-222 level and reduced disease-free survival (P = 0.016) and overall survival (P = 0.012). In multivariate analysis stratified for known prognostic variables, circulating miR-222 was identified as an independent prognostic marker. In conclusion, our findings suggested that circulating miR-222 in plasma might be a potential and useful noninvasive biomarker for the early detection and prognosis of GC.