Published online Jan 15, 2014. doi: 10.4251/wjgo.v6.i1.22
Revised: December 5, 2013
Accepted: December 12, 2013
Published online: January 15, 2014
AIM: To develop a panel of blood-based diagnostic biomarkers consisting of circulating microRNAs for the detection of pancreatic cancer at an early stage.
METHODS: Blood-based circulating microRNAs were profiled by high throughput screening using microarray analysis, comparing differential expression between early stage pancreatic cancer patients (n = 8) and healthy controls (n = 11). A panel of candidate microRNAs was generated based on the microarray signature profiling, including unsupervised clustering and statistical analysis of differential expression levels, and findings from the published literature. The selected candidate microRNAs were then confirmed using TaqMan real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) to further narrow down to a three-microRNA diagnostic panel. The three-microRNA diagnostic panel was validated with independent experimental procedures and instrumentation of RT-qPCR at an independent venue with a new cohort of cancer patients (n = 11), healthy controls (n = 11), and a group of high risk controls (n = 11). Receiver operating characteristic curve analysis was performed to assess the diagnostic capability of the three-microRNA panel.
RESULTS: In the initial high throughput screening, 1220 known human microRNAs were screened for differential expression in pancreatic cancer patients versus controls. A subset of 42 microRNAs was then generated based on this data analysis and current published literature. Eight microRNAs were selected from the list of 42 targets for confirmation study, and three-microRNAs, miR-642b, miR-885-5p, and miR-22, were confirmed to show consistent expression between microarray and RT-qPCR. These three microRNAs were then validated and evaluated as a diagnostic panel with a new cohort of patients and controls and found to yield high sensitivity (91%) and specificity (91%) with an area under the curve of 0.97 (P < 0.001). Compared to the CA19-9 marker at 73%, the three-microRNA panel has higher sensitivity although CA19-9 has higher specificity of 100%.
CONCLUSION: The identified panel of three microRNA biomarkers can potentially be used as a diagnostic tool for early stage pancreatic cancer.
Core tip: This study employed high throughput screening as a screening tool to identify blood-based circulating microRNA markers for detection of early stage pancreatic cancer. Two levels of confirmation were performed to ensure the validity of the identified microRNA targets. First, a panel of potential microRNA markers was generated and confirmed using a more specific and sensitive secondary assay, real-time quantitative reverse transcription polymerase chain reaction. Second, the confirmed panel of microRNA markers was independently validated with different experimental procedures and instruments, by independent personnel, and at a different institution, to diagnose a new cohort of patients and controls.