Rationale for Cytogenetic Risk Stratification by Imaging Flow Cytometry in Multiple Myeloma

Use of Imaging Flow Cytometry for Immunophenotyping Coupled With Cytogenetic Abnormalities Detection by Fluorescent in Situ Hybridization (FISH) and Applicability in Cytogenetic Risk Stratification of Multiple Myeloma (CIF-PM)

A pioneer study demonstrated a proof of concept for IS-FISH with the new ISX technology. This state of the art technology has been recently acquired by the CHU of Amiens. In the present study the investigators want to establish a workflow for simultaneous immunostaining and characterization of FISH cytogenetic pathological signals with the imaging flow cytometer ISX, such as chromosomic gains, losses and translocations in multiple myeloma (MM). The gold standard technology for the detection of prognostic cytogenetic aberrations in MM is a FISH analysis after bone marrow (BM) plasma cells sorting (PCS).2,3 In MM, plasma cells isolation is usually based on CD38 and/or CD138 expression. Cytogenetic risk stratification is guided by the detection of 4 chromosomal aberrations: TP53 and CDKN2C deletions, CKS1B gains and t(4;14) translocation. Thanks to ISX technology the investigators may avoid cumbersome task of cell sorting (outsourced service for our hospital) meanwhile measuring precisely and qualitatively aberrant FISH signals on a large amount of cells.

In a first time (period of 6 months), the development will be performed on CD38 and/or CD138 expressing cell lines. Regular FISH protocols will be finely tuned to fit immunophenotyping and cells in suspension constraints needed in IS-FISH. In a second time, the protocol will be applied to MM BM. Cells from BM aspiration will be processed and analysed on the ISX in Amiens. Based on last years local activity, this step is expected to last 2 years, so as to be able to obtain 5 samples from patients harbouring of each prototypical cytogenetic aberration above described. Inclusions will be guided by the results of PCS conducted before the first treatment initiation. Finally the results will be compared with PCS.

Inclusion Criteria:

• Available BM samples from active MM patients followed in the CHU of Amiens will be selected on the basis of PCS analysis systematically performed before treatment initiation.
• signed consent

Exclusion Criteria:

• <5% plasma cells in BM.
• Pre-bone marrow autograft samples