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Purpose: Circulating microRNAs (miRNA) are emerging as promising diagnostic biomarkers for colorectal cancer, but their usefulness for detecting early colorectal neoplasms remains unclear. This study aimed to identify serum miRNA biomarkers for the identification of patients with early colorectal neoplasms.Experimental Design: A cohort of 237 serum samples from 160 patients with early colorectal neoplasms (148 precancerous lesions and 12 cancers) and 77 healthy subjects was analyzed in a three-step approach that included a comprehensive literature review for published biomarkers, a screening phase, and a validation phase. RNA was extracted from sera, and levels of miRNAs were examined by real-time RT-PCR.Results: Nine miRNAs (miR-18a, miR-19a, miR-19b, miR-20a, miR-21, miR-24, miR-29a, miR-92, and miR-125b) were selected as candidate biomarkers for initial analysis. In the screening phase, serum levels of miR-21, miR-29a, and miR-125b were significantly higher in patients with early colorectal neoplasm than in healthy controls. Elevated levels of miR-21, miR-29a, and miR-125b were confirmed in the validation phase using an independent set of subjects. Area under the curve (AUC) values for serum miR-21, miR-29a, miR-125b, and their combined score in discriminating patients with early colorectal neoplasm from healthy controls were 0.706, 0.741, 0.806, and 0.827, respectively. Serum levels of miR-29a and miR-125b were significantly higher in patients who had only small colorectal neoplasms (≤5 mm) than in healthy subjects.Conclusions: Because serum levels of miR-21, miR-29a, and miR-125b discriminated patients with early colorectal neoplasm from healthy controls, our data highlight the potential clinical use of these molecular signatures for noninvasive screening of patients with colorectal neoplasia. Clin Cancer Res; 21(18); 4234–42. ©2015 AACR.

Supplementary figure 1: Expression levels of serum miR-21, miR-29a and miR-125b in healthy controls (HC) vs. patients with colorectal neoplasms (CRN), after exclusion of 8 patients with colorectal cancer.

Supplementary figure 2: Kaplan Meier survival curves based upon expression levels of miR-21, miR-29a, miR-125b and their combination, when comparing patients with colorectal neoplasms (CRN) with healthy controls (HC), and when comparing patients with advanced neoplasms (AN) with patients without advanced neoplasms (non-AN), after exclusion of all patients with colorectal cancer.

Figure Legends for Supplementary Figures

Objectives: Early detection of precancerous lesions and early-stage cancers are essential to reduce mortality from colorectal cancer (CRC). Serum/plasma microRNAs (miRs) have been reported as diagnostic and prognostic biomarkers of CRC, but their utility in detecting patients with early lesions has not been fully explored. The aim of this study is to identify serum miRs which are potentially useful as diagnostic biomarkers for early colorectal neoplasms, and potential confounders in a blood test. Methods: Candidate biomarker miRs were selected from previously published studies. Serum samples were collected from patients with low-grade intraepithelial neoplasias (LGINs) including tubular adenomas and tubulovillous adenomas, high-grade intraepithelial neoplasias (HGINs), early cancers, and healthy volunteers, and divided into discovery and validation sets. Total RNA was extracted from serum samples and levels of candidate miRs were measured by real-time RT-PCR. To evaluate the impact of hemolysis on serum miR levels, serially diluted hemolysed controls were prepared from stock solution made by hemolysing the red blood cells in distilled water. Levels of candidate miRs in hemolysed controls were also examined by real-time RT-PCR. Absorbance of serum samples at 560 nm, 576 nm, and 592 nm was measured by spectrophotometry and hemoglobin levels were estimated from a standard curve. Results: Fourteen miRs were selected as candidate diagnostic biomarkers of early colorectal neoplasms from a review of the literature. Serum levels of five miRs were too low to be accurately quantified by real-time RT-PCR, and excluded from further evaluation. Sera from 12 patients with LGINs, 8 patients with HGINs, 4 patients with cancers, and 25 healthy volunteers were included in the discovery phase. Of 9 miRs examined, miR21 (p = 0.0007), miR29a (p < 0.0001) and miR125b (p = 0.0198) showed significantly higher levels in sera from early colorectal neoplasms compared to those from healthy volunteers. Higher levels of miR29a and miR125b in sera from early colorectal neoplasms were confirmed in the validation phase using independent set of samples. Levels of miR21, 29a, and miR125b in sera significantly correlated with the degree of hemolysis. Conclusions: Serum miRs may be useful biomarkers to detect patients with early colorectal neoplasia, including adenomas. Hemolysis affects serum miR levels, and will confound measurement. Since hemolysis occurs frequently during blood collection, its impact on serum miRs should be further investigated. Citation Format: Atsushi Yamada, Takahiro Horimatsu, Yoshinaga Okugawa, Naoshi Nishida, Tadayuki Kou, Toshihiro Kusaka, Hajime Honjo, Yusuke Amanuma, Osamu Kikuchi, Manabu Muto, Ajay Goel, C. Richard Boland. Serum microRNAs as diagnostic biomarkers for early colorectal neoplasms. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 867. doi:10.1158/1538-7445.AM2014-867