Prognostic relevance of angiopoietin-2, Fibroblast growth factor-2 and endoglin mRNA expressions in chronic lymphocytic leukemia

Abstract

Elevated levels of circulating angiogenic cytokines and increased expression of genes encoding angiogenic factors have been reported in recent years in patients with chronic lymphocytic leukemia (CLL) but data regarding prognostic and predictive significance are still limited. Therefore, in the present study based upon our prior pilot results, we measured mRNA expressions of angiopoietin-2 (Ang-2), fibroblast growth factor-2 (FGF-2) and endoglin (CD105) by reverse transcription quantitative PCR in purified CD19+ cells from 70 untreated CLL patients (median age, 63 years; males, 64%; Rai III/IV stages, 29 %; unmutated IgVH genes, 60 %) and evaluated their possible association with established prognostic factors and clinical course of the disease. Higher expression of Ang-2 was significantly associated with unmutated IgVH genes (n = 55, p = 0.003). Higher CD105 expression was significantly associated with unmutated IgVH genes (n = 55, p < 0.001), high CD38 expression (n = 66, p = 0.022), high ZAP-70 expression (n = 66, p = 0.010), Rai stage I-IV (n = 70, p < 0.001), progressive clinical course of CLL (n = 70, p = 0.001) and shorter time to treatment (n = 70; p < 0.001). Expression of FGF-2 was not significantly associated with any of the prognostic markers. These results indicate that elevated expression of Ang-2 and in particular CD105 by CLL cells is associated with unfavorable prognostic features and clinical outcome; thus, both cytokines appear to play an important role in biology and progression of CLL and warrant further investigation.