Cerebrospinal fluid ferritin in glioblastoma: evidence for tumor synthesis.

Ferritin concentrations in cerebrospinal fluid (CSF) of 16 patients with glioblastoma were found to be very high (mean, 103.0 ng/mL) relative to 29 patients with viral meningitis and 20 patients with headache (mean concentrations, 5.4 and 4.3 ng/mL respectively). Simultaneous measurement of ferritin in CSF and serum revealed CSF concentrations exceeding those in serum in 11 of 16 patients with glioblastoma (CSF vs. serum ratio, 132.6%), contrasting with very low ratios in patients with meningitis (7.9%) or headache (4.9%). Ferritin was detected immunocytochemically in tumor cell cytoplasm in a resected glioblastoma. Thus, ferritin in CSF appears to be produced by glioblastoma cells, with a biologic significance requiring further investigation.