PF551 CD10 EXPRESSION ON MYELOID PRECURSOR CELLS (CD34 + CD117 +) AS A PREDICTIVE FACTOR FOR PROGRESSION OF PRIMARY MYELODISPLASTIC SYNDROMES

Background: Prognosis assessment of the course of the disease is a clinically important stage in the initial diagnosis of myelodysplastic syndrome (MDS). Analysis of bone marrow cells by flow cytometry allows to identify specific aberrations of both immature and mature cells of various hematopoietic lines. Considering the fact that the definition of MDS includes a diverse group of myeloid neoplasms, the presence of multiple aberrations may be important for diagnostics and risk stratification in patients with MDS. Thus, the assessment of specific immunophenotypic aberrations in MDS blast cells can be a practical tool for predicting the course of the disease and the risk of transformation into acute myeloid leukemia (AML). Aims: To identify the immunophenotypic predictors of AML transformation in myeloid progenitor cells (CD34 + CD117 +) in the bone marrow of adults with primary MDS. Methods: The study included 116 adult patients at the State Medical Center «Minsk Scientific‐Practical Center of Surgery, Transplantology and Hematology» from February 2012 to December 2017 with primary MDS diagnosis. Immunophenotyping was performed before the start of a specific MDS treatment. The median age was 59.1 (interq. range 29:79), among them 62 were males (53%) (median of age 58.7 (interq. range 29.2:78.4) and 54 were females (47%) (median of age 59.1 (interq. range 38:79). Expression of antigens in the bone marrow blast cells was determined using eight‐color flow cytometry on a FACSCanto II instrument (Becton Dickinson, USA). The cytogenetics was performed by a standard G‐banding. Results: A comparative analysis of the time from the initial diagnosis to the disease transformation into AML was performed based on the pattern of expression of immunophenotypic markers on a subpopulation of CD34 + CD117 + myeloid progenitor cells. A marker of asynchronous expression of CD10 was shown as the most significant predictor of disease transformation into AML, and its’ expression does not depend on the MDS variant, according to the WHO classification, and on the presence of cytogenetic aberrations determining unfavorable prognosis, such as anomalies of chromosome 7 and complex karyotype. The presence of aberrant expression of CD10 ≥ 10% on myeloid progenitor cells (CD34 + CD117 +) in MDS patients was found to be associated with a rapid progression of the disease and significantly increased the risk (p = 0.0023) of transformation into AML. It was shown that in the group of patients, who had the expression of CD10 on their bone marrow blast cells, the median time to transformation into AML was 6 months, which is significantly (p < 0.001) shorter than in the group of patients where this aberration was absent, where the median time to transformation into AML was 48 months (Figure 1). Summary/Conclusion: The presence of aberrant expression of CD10 on myeloid progenitor cells (CD34 + CD117 +) is an immunophenotypic predictor of the increased risk of rapid transformation into AML in adult patients with MDS.