Angiogenic Cytokines Are Increased in the Serum of Patients with Waldenastrom’s Macroglobulinemia (WM): Correlations with Clinical Data.

Angiogenesis is essential step of disease progression in several hematologic malignancies including multiple myeloma (MM). Bone marrow (BM) angiogenesis, assessed by microvessel density (MVD), is increased in 30% of patients with WM and showed only weak correlation with BM infiltration. Two major classes of angiogenic factors, namely the vascular endothelial growth factor (VEGF and mainly its A component (VEGF-A)) and angiopoietins 1 and 2 (Ang-1, Ang-2), has been shown to play pivotal role in tumor angiogenesis. Angiogenin is member of the ribonuclease family, which participates in angiogenesis by influencing the migration and proliferation of endothelial cells. Basic fibroblast growth factor (bFGF) is another cytokine, which is produced by stromal cells and plays significant role in MM pathogenesis. Aim of the study was the evaluation of angiogenesis, as assessed by the measurement of the above angiogenic cytokines, in pts with WM and its correlation with clinical data of the pts. We studied serum samples of 67 pts with serum monoclonal IgM (SMIgM) (44M/23F; median age: 71 years, range: 39–85 years) in various phases of their disease. Fifty-three pts had overt WM (21 untreated, 20 in relapse and 12 in remission). Furthermore, 14 pts with IgM MGUS (N=11) or asymptomatic WM (N=3) were also included. VEGF, VEGF-A, angiogenin, angiopoietin-1 and 2 and bFGF were measured using ELISA methodology (Diaclone, France for VEGF-A and R&D Systems, MN, USA for other cytokines). In all pts, we also evaluated hemoglobin, PLT count, β₂-microglobulin (β₂m) and albumin levels as well as the presence of splenomegaly, hepatomegaly and lymphadenopathy at the time of sample collection. The same cytokines were also measured in 30 gender- and age-matched controls. All pts with SMIgM had increased serum levels of all cytokines except angiopoietin-1 compared to controls: mean ±SD for VEGF was 299±228 vs. 106±76 pg/ml in pts and controls, respectively (p<0.0001); for VEGF-A 105±102 vs. 6.7±13.6 pg/ml (p<0.0001), for angiogenin 442.9±216.5 ng/ml vs. 239.5±58.5 ng/ml (p<0.0001); for Ang-1 25.1±22 vs. 21±13.5 ng/ml (p=0,4), for Ang-2 3,212±2,110 vs. 1,746±1,023 pg/ml (p=0.0004) and for bFGF 10.2±17.1 vs. 1.3±3.15 pg/ml (p=0.005). However, pts with IgM MGUS or asymptomatic WM (N=14) had elevated values of Ang-1 (40.16±21.66 ng/ml) compared with controls (p=0.002) and pts with symptomatic WM (p=0.003). Pts with active WM (untreated and relapsed) had increased levels of angiogenin compared with asymptomatic WM-MGUS pts and with pts in remission. At the time of sample collection, 16 pts had anemia (Hb<10 g/dl), while 14 pts had increased levels of β₂m (>3.5 mg/l), and 11 pts had reduced albumin levels (<3.5 g/dl). Pts with high VEGF-A had higher β₂m (r=0.28, p=0.03), high angiogenin was correlated with low albumin (r=−0.39, p=0.001), while high Ang-1 was correlated with low β₂m (r=−0.47, p=0.0009) and high Hb levels (r=0.27, p=0.04). Our study suggests that angiogenic cytokines increase in pts with SMIgM supporting a possible paracrine role of these molecules. Ang-1 is the only cytokine which is increased in pts with IgM-MGUS and asymptomatic WM but returns to normal in pts with symptomatic disease. Our results, if confirmed, may provide the basis for clinical trials in WM, which involve anti-angiogenic agents.