Usefulness of FICTION Method for the Evaluation of Response after Treatment in Multiple Myeloma

• Published in: Blood 2008-11, Vol.112 (11), p.5112-5112
• Main Authors: Lee, Hye Ryun, Kim, Inho, Yoon, Sung-Soo, Park, Seonyang, Kim, Byoung Kook, Kim, Hyun Kyung, Cho, Han Ik, Lee, Dong Soon
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V112.11.5112.5112

Introduction: According to the new uniform response criteria of International Myeloma Working Group (IMWG), stringent complete response (sCR) is defined as a condition of normal free light chain (FLC) ratio and absence of clonal cells in the bone marrow (BM) by immunohistochemistry or immunofluorescence, in addition to the CR condition. The kappa/lambda ratio is assessed to identify clonal cells in the BM and a minimum of 100 plasma cells is required for analysis of clonal cells. However, the evaluation of kappa/lambda ratio by immunohistochemistry or immunofluorescence may be inaccurate, because it is difficult practically to countthe number of anti-kappa/lambda antibodies-stained cells in the BM section and in case of low percentage of residual plasma cells, flow cytometric evaluation is also difficult. To investigate whether FICTION (Fluorescence Immunophenotyping and interphase Cytogenetics as a Tool for the Investigation Of Neoplasms) technique can be used as a tools for evaluation of clonal cells after treatment in multiple myeloma, we performed FICTION on BM cells in follow-up patients with myeloma and compared the results of FICTION with other parameters. Method: 18 myeloma patients, whose BM examination and serum free light chain were checked at the same time after treatment, were enrolled in Seoul National University Hospital. We performed FICTION for the fluorescence in situ hybridization (FISH) items that were abnormal at initial BM examination of each patient. The selected probes were LSI 1q25/1p36/1p subtelomere probe (Vysis, Downers Grobe, IL, USA) for trisomy 1q25, LSI 13 (RB1) 13q14 probe (Vysis) for RB1 deletion, LSI IGH probe (Vysis) for IGH rearrangement and LSI p16 (9p21)/CEP 9 probe (Vysis) for p16 deletion. The FICTION results were reported by the percentage of plasma cells with abnormal FISH signals among plasma cells stained with anti-kappa and lambda antibodies labeled with fluorescein isothiocyanate (FITC). We compared FICTION results with response parameters, such as % plasma cells in BM aspirates, serum FLC ratio, M-component in serum and/or urine protein electrophoresis (PEP) and FISH results. Results: Among 18 patients in follow-up, 5 (28%) showed