Circulating miR-106a is a Novel Prognostic and Lymph Node Metastasis Indicator for Cholangiocarcinoma

Deregulated MicroRNAs in Biliary Tract Cancer: Functional Targets and Potential Biomarkers

Biliary tract cancer (BTC) is still a fatal disease with very poor prognosis. The lack of reliable biomarkers for early diagnosis and of effective therapeutic targets is a major demanding problem in diagnosis and management of BTC. Due to the clinically silent and asymptomatic characteristics of the tumor, most patients are diagnosed at an already advanced stage allowing only for a palliative therapeutic approach. MicroRNAs are small noncoding RNAs well known to regulate various cellular functions and pathologic events including the formation and progression of cancer. Over the last years, several studies have shed light on the role of microRNAs in BTC, making them potentially attractive therapeutic targets and candidates as biomarkers. In this review, we will focus on the role of oncogenic and tumor suppressor microRNAs and their direct targets in BTC. Furthermore, we summarize and discuss data that evaluate the diagnostic power of deregulated microRNAs as possible future biomarkers for BTC.

Diagnostic value of microRNAs as biomarkers for cholangiocarcinoma

BACKGROUND

It has been reported that microRNAs might serve as biomarkers for cholangiocarcinoma (CCA) detection, but their diagnostic accuracy are unclear and controversial.

AIM

To evaluate the diagnostic accuracy of microRNAs for CCA.

MATERIALS AND METHODS

PubMed, Embase, Web of Science and Cochrane Library were systematically searched to identify relevant articles by using the key words "cholangiocarcinoma" and "microRNA". The methodological quality of each study was assessed by QUADAS-2. According to the inclusive and exclusive criteria, 11 articles were identified and analyzed by Meta-disc software v.1.4 and STATA 12.0 software package.

RESULTS

11 articles with 430 CCA patients and 406 controls were identified. The results showed that the pooled sensitivity was 0.756 (95% CI: 0.693-0.810), specificity was 0.914 (95% CI: 0.861-0.947), positive likelihood ratio was 8.747 (95% CI: 5.320-14.381), negative likelihood ratio was 0.267 (95% CI: 0.208-0.341) and diagnostic odds ratio was 32.791 (95% CI: 17.327, 62.060). In addition, the area under the summary ROC cure (AUC) was 0.90 (95% CI: 0.87-0.93).

CONCLUSION

MicroRNAs have great potential as biomarkers for the diagnosis of CCA patients. However, the clinical application of microRNA assays for CCA diagnosis still needs further validation by more prospective studies.

Circulating MicroRNAs as Biomarkers in Biliary Tract Cancers

Biliary tract cancers (BTCs) are a group of highly aggressive malignant tumors with a poor prognosis. The current diagnosis is based mainly on imaging and intraoperative exploration due to brush cytology havinga low sensitivity and the standard markers, such as carcinoembryonic antigen (CEA) and carbohydrate 19-9 (CA19-9), not having enough sensitivity nor specificity to be used in a differential diagnosis and early stage detection. Thus, better non-invasive methods that can distinguish between normal and pathological tissue are needed. MicroRNAs (miRNAs) are small, single-stranded non-coding RNA molecules of ~20–22 nucleotides that regulate relevant physiological mechanisms and can also be involved in carcinogenesis. Recent studies have demonstrated that miRNAs are detectable in multiple body fluids, showing great stability, either free or trapped in circulating microvesicles, such as exosomes. miRNAs are ideal biomarkers that may be used in screening and prognosis in biliary tract cancers, aiding also in the clinical decisions at different stages of cancer treatment. This review highlights the progress in the analysis of circulating miRNAs in serum, plasma and bile as potential diagnostic and prognostic markers of BTCs.

Integrated analysis of mRNA-seq and miRNA-seq in the liver of Pelteobagrus vachelli in response to hypoxia

Pelteobagrus vachelli is a well-known commercial species in Asia. However, a sudden lack of oxygen will result in mortality and eventually to pond turnover. Studying the molecular mechanisms of hypoxia adaptation in fishes will not only help us to understand fish speciation and the evolution of the hypoxia-signaling pathway, but will also guide us in the breeding of hypoxia-tolerant fish strains. Despite this, the genetic regulatory network for miRNA-mRNA and the signaling pathways involved in hypoxia responses in fish have remained unexamined. In the present study, we used next-generation sequencing technology to characterise mRNA-seq and miRNA-seq of control- and hypoxia-treated P. vachelli livers to elucidate the molecular mechanisms of hypoxia adaptation. We were able to find miRNA-mRNA pairs using bioinformatics analysis and miRNA prediction algorithms. Furthermore, we compared several key pathways which were identified as involved in the hypoxia response of P. vachelli. Our study is the first report on integrated analysis of mRNA-seq and miRNA-seq in fishes and offers a deeper insight into the molecular mechanisms of hypoxia adaptation. qRT-PCR analysis further confirmed the results of mRNA-Seq and miRNA-Seq analysis. We provide a good case study for analyzing mRNA/miRNA expression and profiling a non-model fish species using next-generation sequencing technology.