High expression of legumain in acute lymphoblastic leukemia is associated with central nervous system involvement at initial presentation

ABSTRACT: Background. Flow cytometry (FCM) identifies leukemic blasts in cerebrospinal fluid (CSF) in approximately 30% of children with acute lymphoblastic leukemia (ALL), whereas conventional cytospin preparations frequently miss such involvement.
Procedure. To explore biological properties of leukemic cells that migrate into central nervous system (CNS), we compared gene expression profiles of leukemic cells from 26 patients with CNS involvement and 138 patients without CNS leukemia as determined by FCM and/or cytospin preparations. Results were validated by real-time quantitative PCR (qPCR).
Results. We found the cysteine endopeptidase legumain (LGMN) that plays a role in hydrolysis of proteins and small molecules to be significantly differentially expressed between FCM+ and FCM- B-cell precursor (BCP) ALL patients. When LGMN expression was validated by qPCR it stayed differentially expressed between FCM+ and FCM- BCP-ALL patients (P=0.006), and also between FCM+ and cytospin-negative BCP-ALL patients (P=0.01). In multivariate regression analysis including sex, age and WBC, LGMN expression levels above population median were associated with an odds ratio of 9.1 for CNS involvement as determined by FCM compared with expression less than the median (95% CI, 1.26 to 65.50; P=0.03). Conclusions. The use of more sensitive methods for detecting and quantifying CNS involvement, such as FCM, may facilitate detection of markers of leukemia biology, such as LGMN, which could have therapeutical implications for future CNS-directed therapy.
FCM+: Patients had leukemic cells in the cerebrospinal fluid (CSF) detected by flow cytometry and no blood contamination. FCM-: Patients had no leukemic cells in the CSF detected by flow cytometry with or without blood contamination.
CNS1: No leukemic cells in CSF detected by cytospin examination with or without blood contamination and no other clinical signs of central nervous system (CNS) leukaemia. CNS2: CSF leukocyte count <5 x106/µL with blasts on cytospin examination and no blood contamination. CNS3: CSF leukocyte count >5 x106/µL with blasts on cytospin examination and no blood contamination, and/or cranial nerve palsy, and/or CNS leukaemia by neuroimaging.

ORGANISM(S): Homo sapiens

SUBMITTER: Nicolas Rapin 

PROVIDER: E-MTAB-4985 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress