Identification of putative biomarkers for leptomeningeal invasion in B-cell non-Hodgkin lymphoma by NMR metabolomics

Abstract

B-cell non-Hodgkin lymphoma (B-NHL) is the most common hematological malignancy and different genetic alterations are frequently detected in transformed B lymphocytes. Within this heterogeneous disease, certain aggressive subgroups have an increased risk of central nervous system (CNS) involvement at diagnosis and/or relapse, resulting in parenchymal or leptomeningeal infiltration (LI) in 5–15% of cases. The current sensitivity limitations of cerebrospinal fluid (CSF) cytology and contrast-enhanced MRI for CNS involvement, mainly at early stages, motivates the search for alternative diagnostic methods. Here we aim at using untargeted 1H-NMR metabolomics to identify putative biomarkers for LI in B-NHL patients. CSF and peripheral blood samples were obtained from B-NHL patients with a positive (n = 7, LI group) or negative LI diagnostic (n = 13, control group). For seven patients, CSF samples were collected during the course of intrathecal chemotherapy, making it possible to assess the patient´s response to treatment. 1H-NMR spectra were acquired and statistical multivariate and univariate analysis were performed to identify significant alterations. Significant metabolite differences were found between LI and control groups in CSF, but not in serum. A predictive PLS-DA cross-validated model identified significant pool changes in glycine, alanine, pyruvate, acetylcarnitine, carnitine, and phenylalanine. Additionally, increments in protein signals were detected in the LI group. Significantly, the PLS-DA model predicted correctly all samples obtained from the group of patients in remission during LI treatment. The results show that the CSF NMR-metabolomics approach is a promising complementary method in clinical diagnosis and treatment follow-up of LI in B-NHL patients.