Levels of soluble angiogenin in chronic myeloid malignancies: clinical implications

Angiogenesis is critical for the clinical progression of haematopoietic malignancies and depends on angiogenic factors. Angiogenin is a powerful factor produced by neoplastic cells and host microenvironment. High levels of soluble angiogenin (sAng) correlate with a poor prognosis in patients affected by acute myeloid leukaemia and myelodysplastic syndromes, but no data are available on sAng in chronic myeloproliferative disorders (CMD). Therefore, in this study we investigated the clinical significance of the angiogenin in sera of patients with chronic myeloid leukaemia (CML) (n = 14) or essential thrombocythaemia (ET) (n = 20), and correlated them with those of soluble transforming growth factor-beta(1) (sTGF beta(1)). Enzyme-linked immunosorbent assay detected (P < 0.05) higher levels of sAng in CMD compared with healthy subjects (1026.74 +/- 464.60 pg/mL and 196.00 +/- 39.90 pg/mL, respectively). The highest levels of sAng were detected in CML patients (1349.23 +/- 549.55 pg/mL). Interestingly, CML patients who achieved haematological remission after interferon therapy showed circulating levels of angiogenin significantly (P < 0.05) decreased when compared with those at diagnosis. In ET patients, levels of angiogenin (889.34 +/- 267.66 pg/mL) and sTGF beta(1) (76.69 +/-6.08 pg/mL) were higher (P < 0.05) compared with healthy controls (57.93 +/- 19.39 pg/mL). No correlation was found between levels of sAng and levels of sTGF beta(1) or platelet count among ET patients. Our results show for the first time that elevated blood levels of angiogenin feature chronic myeloid malignancies, suggesting a role of angiogenin in the pathogenesis of these diseases.