Among advanced breast cancer patients, brain metastases are a major distant metastasis and associated with poor prognosis. MicroRNAs have a great influence on various oncological functions and have been reported as a potential biomarker for detecting distant metastases. Specific biomarkers and unique mircoRNAs for brain metastases have not yet been reported. The aim of this study was to explore novel microRNAs in serum for leading to brain metastases in the patients with advanced breast cancer using mircoRNA array-based approach.
We retrospectively analyzed the medical records of breast cancer patient and collected clinical data and evaluate the serum microRNA profiles between breast cancer patients with brain metastases and without brain metastases using highly sensitive microarray analysis. All patients underwent brain imaging tests (computed tomography or magnetic resonance imaging). The samples were divided into a training cohort and a test cohort in 2:1 ratio. The training cohort was used to identify microRNAs that could detect brain metastases of breast cancer, and the test cohort was used to validate that microRNAs.
A total of 51 serum samples of breast cancer patients with brain metastases stored in the National Cancer Center Biobank were used. In addition, 28 serum samples were obtained from non-brain metastasis controls. The results showed that two microRNAs (miR-A and miR-B) were found to be able to detect brain metastases of breast cancer. No significant correlation was found between miR-A expression in serum and clinical data. miR-B expression in serum was significantly related to estrogen-receptor (ER) expression in primary breast cancer tissue (P < 0.05).
Serum miR-A and miR-B might be a useful biomarker for predicting brain metastases in breast cancer patients.
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A. Shimomura: I have the following financial relationships to disclose Research funding by AstraZeneca. J. Kawauchi, S. Takizawa: Employee of Toray Industries, Inc. K. Tamura: I have the following financial relationships to disclose. Direct research support to the responsible project lead by Daiichisankyo, MSD, pfizer, AstraZeneca. T. Ochiya: I have the following financial relationships to disclose. Grant/Research funding from: Kyowa Medex, Kewpie Corporation, Takeda, Rohto Pharmaceutical Co., Ltd., Japan Atherosclerosis Research Foundation, Inter Stem, BioMimetics Sympathies. All other authors have declared no conflicts of interest.