The levels of plasma MiR-9 and MiR-106a are associated with the development of peritoneal carcinomatosis in patients with gastric cancer

Abstract This study aimed to investigate the potential value of circulating miRNAs in the diagnosis of peritoneal carcinomatosis (PC) in patients with gastric cancer (GC). A quantitative reverse-transcription polymerase chain reaction (qRT-PCR) method was optimized for the measurement of plasma miRNAs. The concentrations of 11 plasma miRNA transcripts were analyzed in 13 pairs of GC patients with PC (GC/PC) and without PC (GC/NPC) using qRT-PCR. The plasma levels of miR-9 and miR-106a were further validated in 30 pairs of GC/PC and GC/NPC patients, as well as in 35 healthy controls (HC), followed by receiver operating characteristic (ROC) curve analysis. Serum levels of carbohydrate antigen 125 (CA125) and carcinoembryonic antigen (CEA) were also measured. Primary screening and further validation revealed significantly lower plasma miR-9 levels in the GC/PC group than in the GC/NPC and HC groups (p < 0.001). Conversely, plasma miR-106a and serum CA125 levels, but not CEA levels, were significantly higher in the GC/PC group than in the GC/NPC and HC groups (p < 0.001). No significant differences were observed in plasma miR-9 and miR-106a levels between the GC/NPC and HC groups. ROC analyses indicated that plasma miR-9 yielded an area under the curve (AUC) of 0.776 (95% confidence interval [CI] 0.673–0.859, p < 0.001) with 67.4% sensitivity and 93% specificity, and miR-106a had an AUC of 0.830 (95% CI 0.743–0.916, p < 0.001) with 72.1% sensitivity and 83.7% specificity in distinguishing the GC/PC group from the GC/NPC group. Moreover, the diagnostic performances of plasma miR-9 and miR-106a were comparable with that of CA125 (p > 0.05). Kaplan–Meier survival analysis demonstrated that high plasma levels of miR-106a (hazard ratio (HR) = 0.44, 95% CI 0.19–1.00, p = 0.040) and low levels of miR-9 (HR = 0.43, 95% CI 0.18–1.02, p = 0.042) were significantly associated with reduced overall survival in GC/PC patients. Taken together, these findings suggest that plasma miR-9 and miR-106a may serve as promising non-invasive biomarkers for both the diagnosis and prognosis of PC in patients with GC.