Abstract P6-07-24: miR-19b-3p and miR-4687-5p as novel circulating miRNAs as potential prognostic biomarkers in breast cancer
Authors: Tiryakioglu NO , Cabioglu N , Coskunpinar E , Tukenmez M , Ozturk D , Ozkurt E , Igci A , Pence S , Muslumanoglu M 
Published: March 2017

Abstract
Background
Circulating microRNAs (miRNAs) as regulators of gene expression have recntly been promising suitable potential biomarkers due to their stability and ease of detection in blood. In this study, we aimed to determine the plasma expression levels of 372 different miRNAs in patients with invasive ductal breast cancer (IDC).
Methods
The expression levels of 372 circulating miRNAs in plasma samples of 20 patients with operable stage 1-III IDC and 10 healthy controls were determined using RT-PCR arrays. Mean ages of patients and healthy controls were 45.9+/-8.8) and 45.4+/- 5) respectively. Of 20 breast tumors, 12 were luminal breast cancer, whereas 8 were non-luminal as pure HER2-neu or triple negative breast cancer. RNA was isolated using miRNeasy Serum/Plasma Kit (Qiagen, Hilden, Germany, Cat. No: 217004). cDNA synthesis was performed according to manufacturer's instructions with miScript II RT Kit (Qiagen,Hilden, Germany, Cat. No: 218161). Serum/Plasma 384 HC PCR arrays with miScript SYBR Green PCR Kit (Qiagen, Hilden, Germany, Cat. No:218076) were used RT-PCR analysis. These assays included 372 miRNAs in additon to housekeeping genes and reaction controls. All reactions were performed in triplicates. Ct values were analyzed via an online software developed by Sabiosciences. P values were calculated using Student's t-test and p values lower than 0.05 were considered significant.
Results
Among 372 miRNAs, 19 were found to be deregulated in plasma samples of patients with IDC. 8 miRNAs were upregulated, and the other 11 were downregulated.
Upregulated and Downregulated Circulating miRNAs in Patients with Invasive Ductal CarcinomaUpregulated miRNAsFold regulationp valueDownregulated miRNAsFold Regulationp valuemiR-29a-3p2.0240.032miR-19b-1-5p-2.3750.048miR-101-3p2.4000.040miR-4732-5p-2.0910.015miR-542-3p2.2910.042miR-4687-5p-4.6230.005miR-199b-3p2.0190.020miR-3135b-2.7920.0005miR-98-5p2.4830.003miR-4770-2.4150.0103miR-424-5p3.0550.034miR-4301-2.6680.007miR-374c-5p2.1100.049miR-1247-5p-2.8130.0003miR-19b-3p3.7590.048miR-1287-5p-2.2020.0007 miR-197-3p-4.090.023 miR-126-5p-2.0520.029 miR-671-3p-2.5350.014Table 1
miR-19b-3p was the most upregulated miRNA with a fold change of 3.759 (95%CI:1.83- 5.68, p=.048) while miR-4687-5p was the most downregulated with a fold change of 0.216 (95%CI:0.00001-0.43, p=.005).
Conclusion
Our findings indicate that these 19 deregulated circulating miRNAs might be promising biomarker candidates for detection of IDC. The two most deregulated miRNAs were miR-19b-3p and miR-4687-5p. miR19b-3p belongs to a cluster of miRNAs which has been shown to function as oncogenes resulting in the downregulation of tissue factor expression in breast cancer cells. Further validation studies are ongoing in order to determine their clinicopathological prognostic value in breast cancer.
Citation Format: Tiryakioglu NO, Cabioglu N, Coskunpinar E, Tukenmez M, Ozturk D, Ozkurt E, Igci A, Pence S, Muslumanoglu M. miR-19b-3p and miR-4687-5p as novel circulating miRNAs as potential prognostic biomarkers in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-24.