New Diagnostic Technology for the Isolation and Analysis of Live Myeloma Cell from the Blood of Multiple Myeloma Patients
Authors: Kang Hoin , Lee Jihyun , Kim Soee , Lee Ju Bi , Kim Hyo Yong , Kim Min Hyung , Cho Hyeonji , Yoon SangEun , Kim Kihyun , Kim Jungwon 
Published: December 2024

Introduction
Multiple Myeloma (MM) is characterized by the proliferation of abnormal plasma cells within the bone marrow. Abnormal plasma cells are examined by bone marrow (BM) biopsy but it causes great pain to patients, so it is hard to get BM sample frequently for the monitoring of drug efficacy and minimal residual disease. Therefore, the development of new diagnostic method is absolutely necessary for patient's diagnostic convenience. We are developing new diagnostic system for multiple myeloma to isolate and analyze myeloma cells in peripheral blood (PB) using automated CytoGen Smart Biopsy™ platform. In this study, it was performed the feasibility of a technology to isolate myeloma cells from the PB of MM patients and a cross-analysis with clinical data to explore the possibility of utilization of MM diagnosis.
Method
Spiking test using MM cell line (RPMI8226, 200 cells) mixed into human blood samples (5mL, healthy donor) was conducted to check the recovery rate of CytoGen Smart BiopsyTM platform. For the clinical evaluation, patient selection was performed on patients who visited the Department of Hematology and Oncology at Samsung Medical Center (Seoul, Korea) based on the MM diagnosis criteria. We evaluated 9 newly diagnosed patients with MM (ISS I, II, and III (3 per group)) and 2 patients with MGUS. The median age of the MM cohort was 71 years (range 51-84) and 54% were females. Live MM cells in PB (7.5 mL) were isolated by CytoGen Smart BiopsyTM Cell Isolator, subsequently the quantification of number of isolated MM cells in PB was accessed with automated CytoGen Smart BiopsyTM Cell Image Analyzer after immunofluorescence (IF) staining with MM specific markers, CD138 and/or CD38.
Result
In the spiking test with MM cell line, CytoGen Smart BiopsyTM platform showed a high level of recovery rate (over 80%). Clinical evaluation of CytoGen Smart BiopsyTM platform was conducted with 9 MM and 2 MGUS patients. Among the 9 MM patients, more than 100 MM cells in 7.5 mL of PB were observed in all of MM patients except 1 patient with ISS I. In two MGUS, only 3 and 52 cells were observed, respectively. The median value based on ISS staging system was as follows. In stage I: 166 cells, in stage II: 1,739 cells, and in stage III: 2,093 cells were identified. Even a small number of patient samples, an increase tendency in the number of cells by ISS stage was observed. When classified based on R-ISS, the median value for each stage was in stage I: 52 cells, in stage II: 1,737 cells, and in stage III: 5,928 cells, showing a clear tendency to increase by stage. This clinical evaluation clearly demonstrated the possibility of isolation and quantification of MM cells in the PB of MM patients.
Conclusions
Multiple myeloma is a blood cancer showing a very high recurrence rate even after treatment, so a new diagnostic system replacing BM biopsy is absolutely necessary for patient's convenience. Although various methods have been attempted to identify MM cells in the PB, but it was difficult to use it for diagnosis because they could not isolate live MM cells retaining intact MM markers for accurate analysis. In this study, we verified through clinical evaluation that live MM cells in PB can be isolated and analyzed with CytoGen Smart BiopsyTM platform, a size-based separation technology can isolate live MM cells with a large size compared with other PBMCs. Furthermore, we found an increase tendency of MM cells' number in PB by the stage of MM patients. Expanded clinical study will be performed with more MM samples for clinical validation. We expected that further study will be able to identify the correlation between the number of myeloma cells in the PB and prognostic index such as progression-free survival.