Aim: Clonal disorders of hematopoiesis, such as myelodysplastic syndromes (MDS) and myeloproliferative diseases (MPD) are caused by mutations in hematopoietic stem/progenitor cells (HSPC)and functional microenvironmental dysregulation developing through multi-step changes within the hematopoietic stem cell, bone marrow microenvironment and their interaction. Lodgment, proliferation and migration of HSPCs within bone marrow (BM) microenvironment involve cell adhesion to BM extracellular matrix mediated also by laminin. Aim of the study was to clarify interactions between hematopoietic cells and extracellular matrix by laminin immunoexpresion in MDS and MDS/MPD. Methods: Morphologic diagnose were established in 48 patients on BM smears stained by May Grünwald Giemsa and on hemalauneosin stained paraffin sections. Patients were divided in three groups: (1) 26 patients RA, RCMD and RARS ; (2) 12 patients with RAEB-1, RAEB-2 and (3) 10 patients with MDS/MPS. BM sections were immunostained with laminin (Clone 4C7) and positivity between groups was statisticaly compared with Kruskal–Walis test and Chi square test. Results: In second group observed was somewhat lower laminin positivity (median 38 ; range 29–45) than in first (median 44 ; range 28–60) and third group (median 49 ; range 30–60) with borderline statistical difference (P = 0.056). Observed was also laminin positive branching of blood vessels in all three groups and this frequency was significantly lower in first group (P < 0.05). Conclusion: Laminin immunopositivity is one of the methods that can be applied in analysis of angiogenesis in BM of patients with MDS and MDS/MPD. Laminin positive blood vessels branching are one of possible prognostic factor.
