CSF MMP-9 levels in patients with non-Hodgkin's lymphoma of the central nervous system, medulloblastoma and germinal tumour

Some primitive tumours of the central nervous system (CNS) have the peculiarity of diffusing via the cerebrospinal fluid (CSF) with a variable frequency. This characteristic probably correlates with the capacity of neoplastic cells to secrete lytic enzymes active on extracellular matrix proteins. Metalloproteinase-9 and metalloproteinase 2 (MMP-9, MMP-2) have been found in the CSF of patients with primitive glial tumours and with cerebral metastases without correlation with the presence of neoplastic cells in CSF histological study. No data are reported in the literature about metalloproteinase levels in medulloblastoma/PNET and in germinal tumours. We have studied, using an ELISA kit (Quantikine R&D System), serum and CSF MMP-9 levels in 12 patients with medulloblastoma/PNET, 6 patients with germinal tumour, 10 patients with primitive lymphoma, and 10 patients with noninflammatory neurological diseases of the CNS. In CSF we found dosable levels of MMP-9 in 6/12 patients with medulloblastoma/PNET, in 1/6 with germinal tumour and in 2/10 with primitive lymphoma of the CNS. Among 9 patients with dosable MMP-9 levels, none was positive for neoplastic cells by histological study; however, in 2 patients (1 germinoma and 1 medulloblastoma) in whom cytological examination was positive for neoplastic cells in CSF, we have found nondosable CSF MMP-9 levels. The results are discussed in connection with the radiological study (brain and spinal magnetic resonance imaging) and the clinical course of the patients.