Abstract 6686: Tumor suppressor miRNA-665 based serum biomarker for detecting pancreatobiliary cancer
Authors: Mitsunaga Shuichi , Ueno Makoto , Tsuda Masahiro , Kuwahara Takamichi , Takayama Yukiko , Hanada Keiji , Yoshida Hitoshi , Takahashi Kenji , Nakata Kohei , Iwama Hideaki , Ikeda Masafumi , Kobayashi Satoshi , Miki Ikuya , Hara Kazuo , Higuchi Ryota , Shimizu Akinori , Nomoto Tomohiro , Iwamoto Hidetaka , Nakamura Masafumi , Hatano Etsuro , Sudo Hiroko , Takizawa Satoko , Ochiai Atsushi 
Published: April 2023

Abstract
Background: MicroRNA-665 (miR-665), an intracellular inhibitor of pancreatic cancer (PC) cells, might be a potential biomarker to detect pancreatobiliary cancer (PBca). We sought to determine the diagnostic ability of miR-665 as a serum biomarker for PBca, and to explore the role of miR-665 in PC.
Methods: This multicenter study enrolled patients with treatment-naïve PBca and healthy participants. PBca-related serum miRNAs were determined using weighted co-expression network analysis of a comprehensive serum miRNA microarray dataset in an exploratory cohort. Using various combinations of PBca-related serum miRNAs, Fisher’s linear discriminant analyses provided miRNA signatures to discriminate PBca from healthy controls. MiRNA signatures with a sensitivity/specificity (SN/SP) of ≥80/80% and high AUC in comparison with the AUC of CA19-9 were defined as the diagnostic miRNA signature in exploratory, validation and independent validation cohorts, whose accuracy was confirmed by 5-fold cross validation. Biology of the diagnostic miRNAs was evaluated using biopsy samples from liver metastasis of PC patients and human PC cells.
Results: We analyzed 496 of 1487 enrolled subjects (150 healthy and 134 PBca, 50 healthy and 47 PBca, and 50 healthy and 46 PBca subjects in the exploratory, validation and independent validation cohorts, respectively). Among miRNA signatures from 82 PBca-related miRNAs, a five serum miRNA combination containing miR-665 was identified as the diagnostic miRNA signature in all three cohorts. SN/SP and AUC in the validation and independent validation cohorts were 92/88% and 0.95 (CA19-9: 81/92% and 0.94) and 87/80% and 0.91 (CA19-9: 80/98% and 0.87), respectively. In sub-population analysis for detecting 48 resectable PCs, the discriminative ability of the diagnostic miRNA signature plus CA19-9 (SN/SP: 90/78%) was superior in sensitivity to that of CA19-9 alone (60/94%). In seven PC patients with liver metastasis, high expression of intratumor miR-665 tended to correlate with high serum miR-665 level (r = 0.56) and low expression of intratumor phospho-Erk expression (r = 0.57). Transfection of miR-665 to a human PC cell led to cell growth suppression.
Conclusions: This study identified the diagnostic ability of a tumor suppressor miR-665-based serum miRNA signature for PBca. For detecting resectable PC, a miR-665-based serum miRNA signature plus CA19-9 is a superior biomarker to CA19-9 alone.
Citation Format: Shuichi Mitsunaga, Makoto Ueno, Masahiro Tsuda, Takamichi Kuwahara, Yukiko Takayama, Keiji Hanada, Hitoshi Yoshida, Kenji Takahashi, Kohei Nakata, Hideaki Iwama, Masafumi Ikeda, Satoshi Kobayashi, Ikuya Miki, Kazuo Hara, Ryota Higuchi, Akinori Shimizu, Tomohiro Nomoto, Hidetaka Iwamoto, Masafumi Nakamura, Etsuro Hatano, Hiroko Sudo, Satoko Takizawa, Atsushi Ochiai. Tumor suppressor miRNA-665 based serum biomarker for detecting pancreatobiliary cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6686.