Introduction: Gallbladder cancer (GBC) is the most common and aggressive malignancy of biliary tract and has a poor prognosis. Radical surgery is only choice of curative treatment but most of the patients diagnosed with GBC are unresectable. Thus, there is an urgent need of developing the diagnostic biomarkers and therapeutic targets in GBC. Here, we aimed to discover and validate novel regulatory signatures for early diagnosis of patients with GBC.

Methods: Next-generation sequencing (NGS) was performed to identify the dysregulated plasma microRNAs in a discovery phase of patients with GBC (n=17), chronic cholecystitis (CC, n=9) and healthy controls (HC, n=4). The significantly distinct expression of two miRNAs on DESeq2 was validated using real-time PCR in 58 GBC, 20 CC and 10 HC.

Results: Using DESeq2 of high-confidence microRNA data between GBC vs. HC, 312 microRNAs were identified. Of 312 microRNAs, 25 microRNAs were significantly upregulated in GBC than HC. The expression of only a single microRNA hsa-miR-378a-3p was found to be 1.8-fold higher in patients with GBC than CC (p=0.012). During the validation phase, hsa-miR-378a-3p was found to be significantly higher in GBC than CC (P=0.001) and HC (P<0.001), respectively. The second microRNA hsa-miR-423-3p was also upregulated in GBC than HC (P=0.002); its expression was comparable in GBC to CC.

Conclusions: NGS results showed that dysregulated microRNAs profiling were found to be significantly different among patients with GBC than CC and HC. Serum hsa-miR-378a-3p and hsa-miR-423-3p may act as potential non-invasive diagnostic biomarkers for GBC.