Prognostic impact of neuropilin-1 expression in children with B-lineage acute lymphoblastic leukemia

Abstract

Background Neuropilins are transmembrane glycoproteins that act as receptors for vascular endothelial growth factors and are involved in the process of tumor angiogenesis. Objective The aim of this work was to study the prognostic value of neuropilin-1 (NRP-1) expression in children with B-lineage acute lymphoblastic leukemia (ALL). Patients and methods We analyzed NRP-1 expression level in 50 newly diagnosed children with B-lineage ALL and in 20 healthy controls using flow cytometry. Expression of NRP-1 at diagnosis was correlated with standard clinical and laboratory prognostic features. Results The present study revealed a highly significant difference in NRP-1 expression between ALL patients and controls; the mean percentage expression of NRP-1 on bone marrow (BM) blasts of B-ALL patients was 36.86% overall. The highest levels of NRP-1 expression were noted in pre-B-ALL (74.04%) followed by early pre-B-ALL (23.55%) patients, and the lowest expression levels were in mature B-ALL (12.06%) patients, with significant differences between the three subtypes. The expression of NRP-1 was significantly associated with higher white blood cell count, bone marrow blast percentage, and serum lactate dehydrogenase levels at diagnosis. Also, there was a significant association between higher NRP-1 expression and both Philadelphia-positive and CD10-negative ALL types. We found significantly higher levels of NRP-1 expression on BM blasts at diagnosis in patients who relapsed or died compared with those who achieved and maintained complete remission; patients with higher NRP-1 expression had significantly shorter overall survival and disease-free survival than did patients expressing NRP-1 on less than 20% of their BM blasts. Conclusion Our findings suggest that NRP-1 is significantly expressed in children with B-lineage ALL, especially with the pre-B phenotype, and has a bad prognostic impact on the course of this disease.Recommendations We recommend the incorporation of NRP-1 as a prognostic marker in children with B-lineage ALL to offer a chance for intensive therapeutic intervention in patients designated as having poor prognosis, and for studying its role as a potential target for antileukemic and antiangiogenic therapy. Egyptian J Haematol 39:-0 © 2014 The Egyptian Society of Haematology.