Abstract 2577: Circulating micro RNA/isomiRs as novel biomarker of esophageal squamous cell carcinoma
Authors: Ibuki Yuta , Tsutani Yasuhiro , Ueda Daisuke , Koi Yumiko , Tahara Hidetoshi , Okada Morihito 
Published: August 2019

Abstract
Background: Micro RNAs(miRNAs) are small noncoding RNA molecules comprising 19 - 25 nucleotides that regulate the expression of messenger RNA. Micro RNAs are promising diagnostic biomarkers they differ between patients with cancer and healthy individuals. Recent deep sequencing studies have found that highly stable miRNA isoforms(isomiRs) circulate in bloodstream. Although circulating isomiRs could potentially be powerful biomarker like mature miRNAs, their application as cancer biomarkers not been investigated in detail. The present study aimed to determine whether circulating mature miRNAs and isomiRs detected by deep sequencing could serve as biomarkers of esophageal cancer.
Methods: We enrolled serum samples from 62 patients who were histologically diagnosed esophageal squamous cell carcinoma (ESCC) and 60 age and sex matched healthy control (HC) individuals without a history of cancer. The expression of miRNA/isomiRs was investigated using Ion S5 XL sequencer (Thermo Fisher Scientific). Samples were classified into primary (18 ESCC and 12 HC), secondary (30 ESCC and 30 HC), and tertiary (14 ESCC and 18 HC) groups. The definition of a diagnostic biomarker is detected in &gt; 90% of the ESCC and HC samples, mean read numbers significantly differed over twice between them (p &lt; 0.05, t-test). Candidates which met the criteria in the primary group were validated in secondary group. Diagnostic panel was generated using miRNA/isomiRs that consistently confirmed in primary and secondary groups by stepwise multiple linear regression model. Thereafter, accuracy of the diagnostic panel was tested in the tertiary group.
Results: We detected 5452 miRNA/isomiRs at least one sample. Among them, 88 miRNA/isomiRs met the criteria for a diagnostic biomarker in primary group, and were validated in secondary group. As a result, 28 candidates (8 mature miRNAs and 20 isomiRs) met the criteria in primary and secondary group. Multiple linear regression model selected four mature miRNAs and three isomiRs. The index calculated from the panel was significantly higher in patients with ESCC than in the control (87.7 ±11.7 vs. 9.3±1.8, p &lt; 0.001). The area under the receiver operating characteristics (ROC) curves (AUC) of the panel index to predict ESCC patients was 0.993 (95% CI, 0.98 - 1.0, p &lt; 0.001) in the primary and secondary groups, and 0.91 (95% CI, 0.78 - 1.0, p &lt; 0.001) in the tertiary group. The panel index of patients with esophageal adenocarcinoma was significantly lower than that with ESCC (28.5±8.93 vs. 87.7±11.7, p &lt; 0.001). The postoperative panel index tended to be lower than the preoperative index (36.3±5.73 vs. 50.1±37.6, p = 0.13).
Conclusion: To the best of our knowledge, this is the first study to show the usefulness of isomiR to diagnose esophageal cancer. Our diagnostic panel including isomiR had high accuracy and specificity for diagnosing ESCC. IsomiRs detected by deep sequencing could serve as a novel biomarker of ESCC.
Citation Format: Yuta Ibuki, Yasuhiro Tsutani, Daisuke Ueda, Yumiko Koi, Hidetoshi Tahara, Morihito Okada. Circulating micro RNA/isomiRs as novel biomarker of esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2577.