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.

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.

One of the most serious complications faced by inflammatory bowel disease (IBD) is the potential development of colorectal cancer (CRC). There is a compelling need to enhance the accuracy of cancer screening of IBD patients. MicroRNAs (miRNAs) are small non-protein-coding RNAs that play important roles in CRC oncogenesis. In this study, we report differential miRNA expression in IBD patients with associated CRC, from non-neoplastic tissue to dysplasia and eventually cancer. In addition, we identify and examine the role of dysregulated miRNAs in the TP53 pathway. In our CD patients, six miRNAs were up-regulated from non-neoplastic tissue to dysplasia, but down-regulated from dysplasia to cancer (miR-122, miR-181a, miR-146b-5p, let-7e, miR-17, miR-143) (p<0.001). Six differentially expressed miRNAs affected the TP53 pathway (miR-122, miR-214, miR-372, miR-15b, let-7e, miR-17) (p<0.001). Using two human colon cancer cell lines (HT-29 and HCT-116), E2F1, an upstream regulator of TP53, was down-regulated in both cell lines transfected with let-7e (p<0.05) as well as in HCT-116 cells transfected with miR-17 (p<0.05). Additionally, cyclin G, a cell-cycle regulator miR-122 target was down-regulated in both cell lines (p<0.05). Unique differentially expressed miRNAs were observed in CD-associated CRC progression. Six of these miRNAs had a tumorigenic effect on the TP53 pathway; the effect of three of which was studied using cell lines.

OBJECTIVE(S) 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 (BC), pancreatic (PC) and lung (LC) cancer. We identified uniquely dysregulated miRNAs specific for colorectal neoplasia (p<0.05, false discovery rate: 5%, adjusted α=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, miR-374a) were selected based upon p-value, area-under-the-curve (AUC), fold-change, and biological plausibility. AUC (±95% CI) for “Test” cohort comparisons were 0.91 (0.85-0.96), 0.79 (0.70-0.88) and 0.98 (0.96-1.0), respectively. Our mathematical model predicted blinded sample identity with 69-77% accuracy between all neoplasia and controls, 67-76% accuracy between colorectal neoplasia and other cancers, and 86-90% accuracy between colorectal cancer and colorectal adenoma. CONCLUSIONS Our plasma miRNA assay and prediction model differentiates colorectal neoplasia from patients with other neoplasms and from controls with higher sensitivity and specificity compared to current clinical standards.