Abstract 1952: Diagnostic potential of serum and exosomal microRNAs for patients with pre-malignant lesions of colorectal cancer: Detection of adenoma

Abstract

Abstract Background: MicroRNAs (miRNAs) are dysregulated during colorectal cancer (CRC) development and progression. Profiling of CRC tissue has elicited interest in the potential use of miRNAs as non-invasive biomarkers for early detection of CRC. Exosomes have capacity to envelop specific miRNAs, and maintain the integrity of contents in circulation. Therefore, circulating miRNAs in exosomes are more stable than other forms. Thus miRNAs extracted from exosome in serum may have significant potential as disease specific biomarker; however there is no report to assess whether whole serum or exosome-derived miRNAs from serum is a more accurate diagnostic marker and indicator of tumor progression in CRC. This study aimed to evaluate the diagnostic value of serum and exosomal miRNAs for adenoma patients, respectively. Methods: Following a literature review, we investigated the expression of candidate miRNAs in 20 normal colonic mucosa, 27 adenoma, and 19 CRC tissue samples. Then, we quantified their expression in serum and in exosome from 26 adenoma patients and 47 healthy controls to evaluate their clinical significance. Additionally, we compared the expression levels of serum miRNAs with of exosomal miRNAs to investigate their potential as biomarker. Results: We selected four miRNAs, miR-21, miR-29a, miR-92a, and miR-135b, for further investigation. MiR-21, miR-29a, miR-92a, and miR-135b expression in adenoma were significantly higher than in normal colonic mucosa. Regarding the miRNAs expression in serum, miR-21, miR-29a, miR-92a levels in adenoma patients were significantly higher than in healthy controls, and significantly correlated with adenoma size and total adenoma counts in the colorectum. MiR-21, miR-29a and miR-92a levels in serum could significantly discriminate patients with adenoma, and in the patients with advanced adenoma (>1.0 cm), the capacity to discriminate advanced adenoma improved. On the other hand, exosomal miR-21 and miR-29a levels in serum from adenoma patients were significantly higher than that from healthy volunteer. Only exosomal miR-21 significantly correlated with adenoma size and total adenoma counts in the colorectum, and could differentiate patients with adenomas significantly. In the patients with advanced adenoma, the capacity of exosomal miR-21 for biomarker did not improve, and significance disappeared. Conclusion: Our results revealed that although both serum and exosomal miRNAs could be non-invasive biomarkers for the early detection of CRC, but exosomal miRNAs were unfavorable for the identification of high-risk adenomatous polyps. Serum miR-21, miR-29a and miR-92a are potential diagnostic biomarkers in high-risk adenomatous polyp patients. Citation Format: Ryo Uratani, Yuji Toiyama, Takahito Kitajima, Hiroyuki Fujikawa, Jyunichiro Hiro, Minako Kobayashi, Koji Tanaka, Yasuhiro Inoue, Yasuhiko Mohri, Takao Mori, Toshio Kato, Ajay Goel, Masato Kusunoki. Diagnostic potential of serum and exosomal microRNAs for patients with pre-malignant lesions of colorectal cancer: Detection of adenoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1952.