Introduktion.  Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic disorders characterized by ineffective hematopoiesis, persistent cytopenias, and a high risk of progression to acute myeloid leukemia. Although the revised (IPSS-R) and molecular (IPSS-M) prognostic scoring systems are widely used, their accuracy in risk stratification remains limited. Given the central role of the bone marrow microenvironment and angiogenesis in MDS pathogenesis, this study evaluated the prognostic significance of vascular endothelial growth factor (VEGF) serum levels in patients with MDS RAEB-1.

Aim. To determine the optimal serum VEGF threshold in patientswith MDS RAEB-1 and assess its prognostic value for event-freesurvival.

Materials and methods. Twenty-eight patients with MDS RAEB-1 classified as low or intermediate-1 risk according to IPSS were examined. Serum VEGF concentrations were measured by ELISA before and after lenalidomide therapy and correlated with hematological parameters and clinical response.

Results. Patients who achieved complete or partial remission demonstrated a 2.6-fold reduction in VEGF levels, accompanied by decreased bone marrow blast counts and lower proportions of CD34⁺/CD117⁺ cells. In patients with disease stabilization, VEGF levels remained close to baseline. In contrast, non-responders exhibited persistently elevated VEGF, progressive cytopenias, increased blast counts, shortened event-free survival (11.6 ± 3.2 months), and, in some cases, transformation to acute myeloid leukemia.

Conclusions. Serum VEGF represents a dynamic and informative biomarker of disease course in MDS RAEB-1. Its integration into current prognostic models may improve risk stratification accuracy and support the personalization of therapeutic strategies. Serum VEGF informs RAEB-І prognosis.

Keywords: myelodysplastic syndrome, vascular endothelial growth factor, prognostic biomarker, angiogenesis, immunomodulatory therapy.