Quantification Of Cell Surface Hla-A2 And Intracellular Survivin Protein Levels For Tumor Blasts And Non-Blast Immune Cells In Multiple Myeloma Bone Marrow Aspirates Using A Rapid Sample Preservation Methodology Followed By 10-Color Facs Assay.

Abstract Introduction: Multiple myeloma (MM) is a plasma cell disorder characterized by clonal expansion and accumulation of immature undifferentiated neoplastic cells in the bone marrow (BM). Recent advances in fluorochrome chemistries, flow cytometry (FACS) instrumentation and rapid tissue preservation methodologies have created opportunities for broader adoption of FACS in the clinical management of multiple myeloma patients. Methods: We have developed a 10 color, 2 tube FACS assay based on recommendations made by the European Myeloma Network for phenotyping plasma cell gammopathies to identify abnormal blasts in multiple myeloma patient bone marrow aspirates. The assay includes essential plasma cell markers CD138, CD38, CD56 and CD19 to differentiate abnormal blasts from reactive plasma cells. Use of a multi epitope fluorochrome conjugated anti-CD38 antibody enables CD38 detection in patients on anti-CD38 therapy. Results: Quantification of cell surface HLA-A2 and intracellular survivin protein was made possible using fluorochrome conjugated antibodies in combination with bead standards. The SmartTube™ proteomic stabilizer system for rapid preservation was used to freeze BM aspirate specimens for later analysis at locations with appropriate FACS equipment and trained staff. Consistent with previously published literature, patient survivin levels were elevated on abnormal MM blasts in comparison to survivin levels on non-blast immune cells. Conclusion: We have developed a robust FACS methodology that would be easy to implement in the clinical trial and development setting with minimal training. The assay can consistently identify abnormal blasts in BM samples of multiple myeloma patients and quantify intracellular and cell surface biomarkers related to MM disease or disease treatment responses. Citation Format: Tejaswini Hardas, Hyun-Jeong Ra, James Sheridan, Maria Kovalenko, Catherine Tribouley. Quantification of cell surface HLA-A2 and intracellular Survivin protein levels for tumor blasts and non-blast immune cells in multiple myeloma bone marrow aspirates using a rapid sample preservation methodology followed by 10-color FACS assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 408.