Maurice R. Eichenberger

Plasma miR-21: a potential diagnostic marker of colorectal cancer.

Objectives:The main objective of this study was to investigate the potential use of circulating microRNAs (miRNAs) as biomarkers of sporadic colorectal cancer (CRC). Background:CRC, a leading cause of death, is curable if detected early. There is an unmet need for an accurate, noninvasive biomarker of CRC. MiRNAs are non–protein-coding RNAs regulating gene expression that play a role in CRC development. Methods:Levels of 380 miRNAs were determined using microfluidic array technology (Applied Biosystems) in a “training” set of 30 CRC patients from whom cancer and adjacent normal tissue were collected. The 4 most dysregulated miRNAs (P < 0.05, false discovery rate (FDR): 10%) were then validated in a second blinded “test” set of 16 CRC patients from whom cancer and normal adjacent tissue had been collected. Validated tissue miRNAs were then evaluated in a plasma “test” set consisting of 30 CRC patients and 30 individuals without CRC. The most dysregulated tissue miRNAs were then validated in an independent new plasma test set consisting of 20 CRC patients with 20 age-, -, and race-matched subjects without CRC. Results:Nineteen of 380 miRNAs were dysregulated in CRC tissue in the tissue “training” set (P < 0.05, FDR: 10%). The 2 most upregulated (miR-31; miR-135b) and most downregulated (miR-1; miR-133a) miRNAs identified CRC in our “test” set with 100% sensitivity and 80% specificity. MiR-31 was more upregulated in stages III and IV compared with stages I and II (P < 0.05). In the “plasma” group, miR-21 differentiated CRC patients from controls with 90% specificity and sensitivity. Conclusions:Plasma miRNAs provide reliable and noninvasive markers for CRC. Plasma miR-21 warrants study in larger cohorts. It seems uniquely promising as a plasma biomarker for CRC.

A plasma microRNA panel for detection of colorectal adenomas: a step toward more precise screening for colorectal cancer.

Objective:The main objective of this study was to investigate the potential use of circulating microRNAs (miRNAs) as biomarkers of colorectal (CR) adenomas. Background:Detection of precancerous lesions such as CR adenoma is a key to reduce CR cancer (CRC) mortality. There is a great need for accurate, noninvasive biomarkers for detection of CR adenoma and CRC. MiRNAs are non-protein-coding RNAs that regulate gene expression. Our prior work investigated the dysregulation of 5 plasma miRNAs in CRC patients. As intended, we undertook a more comprehensive plasma-miRNA screening study in patients with CR adenoma and CRC. Methods:We screened for 380 plasma-miRNAs using microfluidic array technology (Applied BioSystems) in a screening cohort of 12 healthy controls, 9 patients with CR adenomas, and 20 patients with CRC. A panel of the most dysregulated miRNAs (P < 0.05, False Discovery Rate: 5%) was then validated in a blinded cohort of 26 healthy controls, 16 patients with large adenomas, and 45 patients with CRC. Results:A panel of 8 plasma miRNAs (miR-532-3p, miR-331, miR-195, miR-17, miR-142-3p, miR-15b, miR-532, and miR-652) distinguished polyps from controls with high accuracy [area under curve (AUC) = 0.868 (95% confidence interval [CI]: 0.76–0.98)]. In addition, a panel of 3 plasma miRNAs (miR-431, miR-15b, and miR-139-3p) distinguished Stage IV CRC from controls with an [AUC = 0.896 (95% CI: 0.78–1.0)]. Receiver-operating-characteristic curves of miRNA panels for all CRC versus controls and polyps versus all CRC showed AUC values of 0.829 (95% CI: 0.73–0.93) and 0.856 (95% CI: 0.75–0.97), respectively. Conclusions:Plasma miRNAs are reliable, noninvasive, and inexpensive markers for CR adenomas. This miRNA panel warrants study in larger cohorts. Plasma-based assays could provide better screening compliance compared to fecal occult blood or endoscopic screening.

A Highly Predictive Model for Diagnosis of Colorectal Neoplasms Using Plasma MicroRNA: Improving Specificity and Sensitivity.

Objective: To develop a plasma-based microRNA (miRNA) diagnostic assay specific for colorectal neoplasms, building upon our prior work. Background: Colorectal neoplasms [colorectal cancer (CRC) and colorectal advanced adenoma (CAA)] frequently develop in individuals at ages when other common cancers also occur. Current screening methods lack sensitivity, specificity, and have poor patient compliance. Methods: Plasma was screened for 380 miRNAs using microfluidic array technology from a “Training” cohort of 60 patients, (10 each) control, CRC, CAA, breast cancer, pancreatic cancer, and lung cancer. We identified uniquely dysregulated miRNAs specific for colorectal neoplasia (P < 0.05, false discovery rate: 5%, adjusted &agr; = 0.0038). These miRNAs were evaluated using single assays in a “Test” cohort of 120 patients. A mathematical model was developed to predict blinded sample identity in a 150 patient “Validation” cohort using repeat-sub-sampling validation of the testing dataset with 1000 iterations each to assess model detection accuracy. Results: Seven miRNAs (miR-21, miR-29c, miR-122, miR-192, miR-346, miR-372, and miR-374a) were selected based upon P value, area under the curve (AUC), fold change, and biological plausibility. Area under the curve (±95% confidence interval) for “Test” cohort comparisons were 0.91 (0.85–0.96) between all neoplasia and controls, 0.79 (0.70–0.88) between colorectal neoplasia and other cancers, and 0.98 (0.96–1.0) between CRC and colorectal adenomas. In our “Validation” cohort, our mathematical model predicted blinded sample identity with 69% to 77% accuracy, 67% to 76% accuracy, and 86% to 90% accuracy for each comparison, respectively. Conclusions: Our plasma miRNA assay and prediction model differentiate colorectal neoplasia from patients with other neoplasms and from controls with higher sensitivity and specificity compared with current clinical standards.

Evaluation of SLC11A1 as an inflammatory bowel disease candidate gene

BackgroundSignificant evidence suggests that a promoter polymorphism withinthe gene SLC11A1 is involved in susceptibility to both autoimmune and infectious disorders. The aim of this study was to evaluate whether SLC11A1 has a role in the susceptibility to inflammatory bowel disease (IBD) by characterizing a promoter polymorphism within the gene and two short tandem repeat (STR) markers in genetic proximity to SLC11A1.MethodsThe studied population consisted of 484 Caucasians with IBD, 144 population controls, and 348 non-IBD-affected first-degree relatives of IBD patients. IBD subjects were re-categorized at the sub-disease phenotypic level to characterize possible SLC11A1 genotype-phenotype correlations. Polymorphic markers were amplified from germline DNA and typed using gel electrophoresis. Genotype-phenotype correlations were defined using case-control, haplotype, and family-based association studies.ResultsThis study did not provide compelling evidence for SLC11A1 disease association; most significantly, there was no apparent evidence of SLC11A1 promoter allele association in the studied Crohns disease population.ConclusionOur results therefore refute previous studies that have shown SLC11A1 promoter polymorphisms are involved in susceptibility to this form of IBD.

Genetic polymorphisms predict response to anti-tumor necrosis factor treatment in Crohn’s disease

AIM To investigate genetic factors that might help define which Crohn’s disease (CD) patients are likely to benefit from anti-tumor necrosis factor (TNF) therapy. METHODS This was a prospective cohort study. Patients were recruited from a university digestive disease practice database. We included CD patients who received anti-TNF therapy, had available medical records (with information on treatment duration and efficacy) and who consented to participation. Patients with allergic reactions were excluded. Patients were grouped as ever-responders or non-responders. Genomic DNA was extracted from peripheral blood, and 7 single nucleotide polymorphisms (SNPs) were assessed. The main outcome measure (following exposure to the drug) was response to therapy. The patient genotypes were assessed as the predictors of outcome. Possible confounders and effect modifiers included age, gender, race, and socioeconomic status disease, as well as disease characteristics (such as Montreal criteria). RESULTS 121 patients were included. Twenty-one were non-responders, and 100 were ever-responders. Fas ligand SNP (rs763110) genotype frequencies, TNF gene -308 SNP (rs1800629) genotype frequencies, and their combination, were significantly different between groups on multivariable analysis controlling for Montreal disease behavior and perianal disease. The odds of a patient with a Fas ligand CC genotype being a non-responder were four-fold higher as compared to a TC or TT genotype (P = 0.009, OR = 4.30, 95%CI: 1.45-12.80). The presence of the A (minor) TNF gene -308 allele correlated with three-fold higher odds of being a non-responder (P = 0.049, OR = 2.88, 95%CI: 1.01-8.22). Patients with the combination of the Fas ligand CC genotype and the TNF -308 A allele had nearly five-fold higher odds of being a non-responder (P = 0.015, OR = 4.76, 95%CI: 1.35-16.77). No difference was seen for the remaining SNPs. CONCLUSION The Fas-ligand SNP and TNF gene -308 SNP are associated with anti-TNF treatment response in CD and may help select patients likely to benefit from therapy.