[The clinical significance of angiogenesis in the bone marrow of acute leukemia patients].

Objective: To study the angiogenesis in bone marrow and the level of vascular endothelial growth factor (VEGF) in bone marrow fluid from acute leukemia (AL) patients and to explore their clinical significance.

Methods: Microvessels in each bone marrow specimen section were counted by immunohistochemical identification of microvascular endothelial cells with anti-human von Willebrand factor under light microscopy in field 400 times. The VEGF level in bone marrow fluid was measured by ELISA.

Results: Microvessel counts in untreated AL patients (22.82/x 400 field) were significantly higher than those in normal controls (7.17/x 400 field) and in the bone marrow remission (BMR) AL patients (8.57/x 400 field) (P < 0.001, both), while the controls in the latter were higher than those in controls (P < 0.05). There was no difference in microvessel counts between untreated AL patients and relapse/refractory AL patients (21.83/x 400 field) (P > 0.05). In the untreated AL group, the microvessel counts showed difference neither between 23 ALL patients (23.09/x 400 field) and 43 ANLL patients (22.37/x 400 field) (P > 0.05), nor between patients with M(1 - 3) (22.91/x 400 field) and M(4 - 5) (21.46/x 400 field) the two subtypes of FAB (P > 0.05). There was a positive correlation between the microvessel counts and the percentage of blast cells in the bone marrow (r = 0.311, P < 0.01). The VEGF level in the bone marrow fluid in untreated AL patients (188.88 ng/L) was significantly higher than that in BMR AL patients (78.74 ng/L) and controls (79.52 ng/L) (P < 0.01), while the latter two groups had no difference between each other (P > 0.05). The VEGF level in the bone marrow fluid from ANLL group (270.12 ng/L) was enhanced significantly compared with that from ALL group (101.70 ng/L) (P < 0.01) and associated with the microvessel counts (r = 0.464, P < 0.05).

Conclusion: Microvessel counts increased in the bone marrow in patients with different types of AL, suggesting that angiogenesis might play an important role in the pathology of AL. Testing the VEGF level in the bone marrow fluid from ANLL patients could reflect the degree of angiogenesis and disease condition.