Angiogenesis is a process of formation of new vessels from the preexisting ones. It is involved in many physiological processes, at the same time, however, it is involved also in the progress of tumoral growth. Although a lot is known about angiogenesis in solid tumors where it plays a role in tumoral invasion and its metastatic potential, in hematological malignancies it has been appreciated only recently. However, the results of studies on abnormal angiogenesis in hematological malignancies are inconsistent. Angiogenesis can be studied at different levels; histologically, it is studied in the infiltrated tissues (lymph nodes, bone marrow) and quantified as microvessel density (MVD). The aims of our study were to introduce the method of MVD quantification in the bone marrow using immunohistochemical detection of endothelial markers (fVIII) and then evaluate MVD in bone marrow samples in a group of patients with chronic lymphocytic leukaemia (CLL) and compare the results with a control group of patients (CON). CLL is a typical malignancy of the hematopoietic tissue but the course and the prognosis of patients with this disease vary considerably. For this reason there is urgent need for novel prognostic markers in order to assess individual patient prognosis and tailor treatment. Angiogenesis is one of the possible markers which may add more informations about the course of this disease. So far only few studies have been published about angiogenesis measured as MVD in CLL patients and the results are inconsistent. In our study, both the number and the area of microvessels were increased in bone marrow of patients with CLL, but the number and area of sinuses were not. It can be concluded that there are signs of abnormal angiogenesis in bone marrow of patients with CLL but larger study with longer follow-up is needed to give more specific information about prognostic value of these findings.

        Key words: angiogenesis – bone marrow – chronic lymphocytic leukaemia – CLL – microvessel density – MVD