Novel method for the detection of circulating tumor plasma cells in multiple myeloma.

Abstract

e19520 Background: Multiple Myeloma (MM) is characterized by the proliferation of abnormal plasma cells within the bone marrow. A bone marrow examination is essential for the diagnosis of multiple myeloma. This is a test that causes great pain to patients because it requires collecting and analyzing the bone marrow fluid inside the bone. In addition, there is a disadvantage that it cannot be carried out frequently due to cost issues. Therefore, the development of new diagnostic methods is absolutely necessary. The aim of this study is to access the potential of circulating tumor plasma cells (CTPC) for the diagnosis of MM using CytoGen's Smart Biopsy platform. Methods: Spiking tests using MM cell line (RPMI8226) was conducted with the purpose of making an environment similar to the MM patient's blood. RPMI8226 cells (200 cells) stained with CellTracker were spiked into human blood sample (5mL, healthy donor). Then, spiked cells were isolated by CytoGen’s Smart Biopsy isolator, subsequently recovery rate was accessed by counting of isolated RPMI8226 or immunofluorescence (IF) staining with multiple myeloma-specific marker, CD138. Then, clinical evaluation was performed with bone marrow (3mL) and peripheral blood (5mL) samples of MM patients (n=20). The presence of CTPC in patient samples was tested by IF staining with anti-CD138 antibody. Results: In in vitro experiments to test recovery rate of CTPC using CytoGen's Smart Biopsy isolator, MM cell line’s recovery rate was validated to over 80%. CD138 expression was clearly detected by IF staining of spiking samples of multiple myeloma cell line and was not detected at all in the negative controls. In clinical evaluation study, CTPC was successfully observed after the isolation from bone marrow and peripheral blood using CytoGen's Smart Biopsy isolator by IF staining with CD138. Conclusions: This study shows a novel method for the detection of MM with liquid biopsy. CTPC from liquid biopsy of MM could be isolated using CytoGen's Smart Biopsy isolator with high recovery rate and can clearly be detected with specific marker of MM, CD138 by IF staining. These results suggested that CytoGen's Smart Biopsy platform might be an effective diagnostic tool for the detection of MM. Expanded clinical study will be performed with more MM samples for clinical validation. Clinical trial information: 2013-09-009 .