[Study on the role of angiogenesis and related factors in leukemias].

Objective: To observe the bone marrow angiogenesis in leukemia and evaluate the expression and role of endostatin (ES), vascular endothelial growth factor (VEGF) and its receptor (VEGFR) in leukemia patients.

Methods: Bone marrow angiogenesis was assayed by vWF immunohistochemical method. The ES and VEGF concentrations in plasma were detected by ELISA. The expression of VEGFR in leukemia cells was determined by flow cytometry (FCM).

Results: The bone marrow microvessel density (MVD) in 26 cases of acute leukemia (AL) [(20.78 +/- 7.75)/high-power field (HP)] and 5 chronic myelogenous leukemia (CML) [(28.67 +/- 7.32)/HP] at newly diagnosed stage was significantly higher than that in the control group [(9.29 +/- 3.53)/HP, P < 0.01]. The bone marrow MVD in the complete remission (CR) groups, (11.33 +/- 5.66)/HP for AL and (17.00 +/- 8.04)/HP for CML, was significantly lower than that of newly diagnosed groups (P < 0.05 and < 0.01). No significant difference was found between the remission groups and the control group (P > 0.05). The plasma ES and VEGF concentrations of newly diagnosed AL and CML groups were significantly higher than those of the control group (P < 0.05). The levels of plasma ES and VEGF in AL CR group and plasma ES in CML CR group decreased to levels comparable to normal values (P > 0.05), but the plasma VEGF in CML CR group was still higher than that in control (P < 0.01). AL bone marrow mononuclear cells had higher expression of VEGFR at various levels whereas CML and control samples had lower levels of VEGFR.

Conclusions: Leukemia patients at newly diagnosed stage had remarkable angiogenesis in bone marrow and elevated plasma ES and VEGF concentrations. VEGFR was expressed at different levels in AL cells.