Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Early screening for colorectal cancer(CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is anappealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Novel blood-based microRNA biomarker panel for early diagnosis of pancreatic cancer

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 proce-dures 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.