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The clinical significance of negative flow cytometry immunophenotypic results in a morphologically scored positive bone marrow in patients following treatment for acute myeloid leukemia
Author(s) -
Ouyang Juan,
Goswami Maitrayee,
Tang Guilin,
Peng Jie,
Ravandi Farhad,
Daver Naval,
Routbort Mark,
Konoplev Sergej,
Lin Pei,
Medeiros L. Jeffrey,
Jorgensen Jeffrey L.,
Wang Sa A.
Publication year - 2015
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.23988
Subject(s) - immunophenotyping , cebpa , minimal residual disease , npm1 , bone marrow , fluorescence in situ hybridization , medicine , cytogenetics , pathology , myeloid , myeloid leukemia , leukemia , gastroenterology , flow cytometry , immunology , karyotype , biology , mutation , biochemistry , chromosome , gene
In a patient with acute myeloid leukemia (AML) following therapy, finding ≥5% bone marrow (BM) blasts is highly concerning for residual/relapsed disease. Over an 18‐month period, we performed multicolor flow cytometry immunophenotyping (MFC) for AML minimal residual disease on >4,000 BM samples, and identified 41 patients who had ≥5% myeloblasts by morphology but negative by MFC. At the time of a negative MFC study, an abnormal cytogenetic study converted to negative in 14 patients and remained positive at a low level (2.5–9.5%) by fluorescence in situ hybridization in 3 (14%), of the latter, abnormalities subsequently disappeared in the repeated BM in 2 patients. Positive pretreatment mutations, including FLT3, NPM1, IDH1, CEBPA, became negative in all 10 patients tested. Of the seven patients with favorable cytogenetics, PML/RARA, CBFB‐MYH11 or RUNX1‐RUNX1T1 fusion transcripts were detected at various levels in six patients but all patients remained in complete remission. With no additional chemotherapy given, 39 patients had BM repeated (median 2 weeks, range <1–21), and all cases showed <5% BM blasts and a continuously negative MFC. In the end of follow‐up (median 10 months, range 1–22), 13 patients experienced relapse, 12/13 showing clonal cytogenetic evolution/switch and 11 demonstrating major immunophenotypic shifts. We conclude that MFC is useful in identifying a regenerating BM sample with ≥5% BM blasts that would otherwise be scored as positive using standard morphologic examination. We believe this conclusion is supported by the changes in molecular cytogenetic status and the patient clinical follow‐up data. Am. J. Hematol. 90:504–510, 2015. © 2015 Wiley Periodicals, Inc.