title: Cathepsin B and H activities and cystatin C concentrations in cerebrospinal fluid from patients with leptomeningeal metastasis.
abstract: BACKGROUND
  Cysteine proteases are involved in the extension of cancer into the subarachnoid space. The presence of cathepsins B and H along with their potent inhibitor cystatin C in the cerebrospinal fluid (CSF) was investigated in patients with leptomeningeal metastasis of cancer (LM).
  
  
  METHODS
  CSF samples were obtained in 16 cases of LM (10 solid tumors and 6 leukemia or lymphoma) and compared with 11 cancer cases without involvement of the central nervous system, 12 multiple sclerosis cases and 34 healthy volunteers. The activity of the enzymes was measured, their molecular forms were analyzed by the Western blotting, and the concentration of cystatin C was measured by ELISA. Immunohistochemistry of the leptomeningeal tissues was also performed in six autopsy cases of LM.
  
  
  RESULTS
  High activities of cathepsins B and H along with decreased cystatin C concentration were observed in CSF of LM as compared with three control groups. Western blot analysis revealed higher concentration of the enzyme protein as well as its active forms in samples with higher enzyme activity. Cells metastasizing leptomeningeal tissue were clearly positive in immunohistochemical staining of cathepsins, indicating active production by tumor cells.
  
  
  CONCLUSIONS
  Production of cathepsins B and H by tumor cells and their high activity along with concomitant decrease of their potent inhibitor, cystatin C, in the CSF might contribute in the process of metastasis and spread of the cancer cells in the leptomeningeal tissues. A high enzyme activity/cystatin C concentration ratio in the CSF could be useful when diagnosing LM in combination with other parameters.
authors.affiliation: Department of Internal Medicine III, Shimane Medical University, Izumo, Japan. anagai@shimane-med.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagai
authors.forename: Masaharu
authors.initials: M
authors.lastname: Terashima
authors.forename: Takayuki
authors.initials: T
authors.lastname: Harada
authors.forename: Koichi
authors.initials: K
authors.lastname: Shimode
authors.forename: Hiromi
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Yohko
authors.initials: Y
authors.lastname: Murakawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Nagasaki
authors.forename: Akinobu
authors.initials: A
authors.lastname: Nakano
authors.forename: Shotai
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D015153:Blotting, Western; D002401:Cathepsin B / Q000134:cerebrospinal fluid*; D056655:Cathepsin H; D002403:Cathepsins / Q000134:cerebrospinal fluid*; D002452:Cell Count; D002555:Cerebrospinal Fluid / Q000166:cytology; D055316:Cystatin C; D015891:Cystatins / Q000134:cerebrospinal fluid*; D003546:Cysteine Endopeptidases / Q000134:cerebrospinal fluid*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D007938:Leukemia / Q000473:pathology; D008577:Meningeal Neoplasms / Q000134:cerebrospinal fluid* / Q000473:pathology / Q000556:secondary*; D009362:Neoplasm Metastasis
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534126:CTSH protein, human; D056655:Cathepsin H