Both disseminated tumor cells and noncancerous host cells contributed to cancer progression cooperatively in bone marrow. Bone marrow samples were obtained from 4 gastric cancer patients, and were separated into 3 fractions (CD45 positive, CD45 negative/EpCAM positive, and CD14 positive fractions) by the automagnetic-activated cell separation (AutoMACS) system using CD45, EpCAM, and CD14 microbeads (Miltenyi Biotec, Germany). microRNA expression profiles in each fractions were evaluated in order to identify candidate prognostic markers for gastric cancer patients.
Overall design: In 4 patients with gastric cancer, bone marrow samples (40 mL) were obtained from iliac bones. Nucleated cells were collected by gradient centrifugation using Ficoll-Paque PREMIUM (GE Healthcare Life Science, USA) and Leucosep (Greiner Bio-One, Germany) according to the manufacturer’s instructions. Next, we separated bone marrow cells into 3 fractions using MACS: CD45 positive (CD45+), CD45 negative/EpCAM positive (CD45-/EpCAM+), and CD14 positive (CD14+). microRNA expression levels of whole bone marrow cells and each fractions were measured by the miRCURY™ LNA array microarray (6th gen-hsa, mmu & rno#208402, Exiqon, Vedbaek, Denmark). The miRCURY™ LNA array microarray slides were scanned using the Agilent G2505C Microarray Scanner System (Agilent Technologies, Inc., USA) and the data analysis was carried out using the Feature Extraction 10.7.3.1 (Agilent Technologies, Inc., USA).
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