Introduction: Neuropilins are single-pass transmembrane glycoproteins acting as receptors for the vascular endothelial growth factor (VEGF) family that mediates angiogenesis and vascular development. In Acute Myeloid leukemia (AML), Neuropilin-1 high expression was found to contribute in disease evolution.

Aim of Work: To evaluate Neuropilin-1 (NRP-1) expression in AML patients especially monocytic subtypes and assess its role in disease progression and extramedullary invasion (EMI).

Patients and Methods: We measured NRP-1 expression level in 50 denovo AML patients who presented to the National Cancer institute, Cairo university. Expression was assessed by Real time quantitative PCR (RQ-PCR) using normalized copy number equation (2 -ΔΔ CT) in relation to normal healthy controls. AML patients were characterized according to their Bone marrow and peripheral blood morphology, karyotype, immunophenotyping and FLT3 internal tandem duplication (FLT3-ITD) by polymerase chain reaction (PCR). Patients were classified into 2 groups according to median NRP-1 expression into low ≤60 and high >60-fold expression.

Results: 33 males (66%) and 17 females (34%) with a median age of 34 years (18-73) were included. Cytogenetic risk categories were low in 12 (24%), intermediate in 34 (68%) and high in 4 (8%) patients. No correlation was found between high NRP-1 and cytogenetic risk classes or FLT3-ITD.

Out of 26 patients showing high NRP-1 expression; 19 (73%) were <40 years vs. 7(27%) >40 years (p=0.049) and 24 (92%) showed BM blasts >50% vs. 2 (8%) with < 50% BM blasts (p<0.001). A positive correlation was found between NRP-1 Fold -change and BM blasts (r=0.653, p=0.004). Out of 19 monocytic FAB subtypes (M4, M5), high NRP-1 expression was expressed in 16 (84%) vs. 10/31 (32%) patients presenting with other FAB subtypes (p=0.042). Out of 26 patients showing high NRP-1 expression, extramedullary invasion (EMI) was found in 23/26 (88%) vs. 3/26 (12%) patients only with no EMI (p=0.001).

Conclusion: Neuropilin-1 is useful as a prognostic marker of extramedullary invasion for AML patients especially in monocytic subtypes . Its role in disease progression and severity is still to be evaluated in our patients.

Key Words: Neuropilin-1, AML, extramedullary invasion

Figure.
Figure.
View largeDownload slide
Disclosures

No relevant conflicts of interest to declare.

Topics:
leukemia, myelocytic, acute, monocytes, neuropilin-1, polymerase chain reaction, ms-like tyrosine kinase 3, disease progression, impedance threshold device, vascular endothelial growth factor a, blood cell morphology, glycoprotein

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2018 by The American Society of Hematology
2018
Sign in via your Institution