The serum concentration of two pro-angiogenic cytokines: basic fibroblast growth 
factor (bFGF) and transforming growth factor beta1 (TGF-beta1), and 
anti-angiogenic factor endostatin in the serum of 80 never treated B-cell 
chronic lymphocytic leukemia (CLL) patients and 27 healthy volunteers was 
measured using an enzyme linked immunosorbent assay. The serum levels of both 
bFGF and TGF-beta1 were found to be significantly higher in the CLL group 
(median 40.5 pg/ml and 38.6 ng/ml respectively) when compared to the control 
group (median 9.4 pg/ml and 18.9 ng/ml, respectively) (p<0.001). The levels of 
endostatin were not significantly different in CLL and control groups (median 
12.3 ng/ml and 8.4 ng/ml, respectively) (p=0.09). In the group of CLL patients 
the level of bFGF was significantly higher in patients with progressive disease 
as compared with patients with stable disease (median 90.5 pg/ml and 40.5 pg/ml 
respectively) (p<0.001). Patients in Rai stage III and IV also had significantly 
higher levels of bFGF than patients in Rai stage 0-II (median 100.1 pg/ml and 
29.3 pg/ml respectively) (p<0.001). The levels of both TGF-beta1 and endostatin 
were lower in patients in Rai stage III and IV (median 28.9 ng/ml and 9.1 ng/ml 
respectively) than in patients in Rai stage 0-II (42.8 ng/ml and 13.1 ng/ml 
respectively) (p<0.001 and p=0.002 respectively). The level of endostatin was 
also lower in the group of CLL patients with progressive disease (median 10.0 
ng/ml) as compared to patients with stable disease (median 20.5 ng/ml) 
(p=0.008). In conclusion, the disturbance in the balance between pro- and 
anti-angiogenic factors may have an important influence on the course of CLL.