[Polysialylated NCAM in CSF, a marker for invasive medulloblastoma].
We described a double-site enzyme-linked immunosorbent assay (ELISA) to measure polysialic acid neural cell adhesion molecule (PSA-NCAM) level in CSF. Immunocapture of PSA-bearing molecules is first effected by means of a monoclonal antibody (anti-MenB), directed against sialic acid polymers and adsorbed into plastic wells. Linked PSA-NCAM is then revealed by means of a second antibody, directed against an aminoacid sequence of NCAM and labelled with peroxydase. The lowest amount of PSA-NCAM detectable was estimated to be 0.11 microgram/l. This value was considered as the threshold for positivity. PSA-NCAM level was measured using this method in CSF from 29 patients with medulloblastoma. CSF had been collected at different times following tumor excision and stored at--80 degrees C. At the same times, cytological examination in CSF (medulloblastoma metastatic cells) and craniospinal imaging (tomographic scan or MRI) had been performed. PSA-NCAM was never detected in control CSF. For patients in remission, beyond the post-operative period of 1 or 2 months, 18 on 21 exhibited a PSA-NCAM level below the threshold value. For refractory patients, so classified according to the positivity of cytology and/or imaging, whatever the time after the tumor excision, PSA-NCAM was always positive (23/23), while either cytology or imaging were positive less frequently (16/23 for both). For relapses, PSA-NCAM was more frequently positive (6/7) than cytology and imaging (1/7 and 5/7, respectively). We concluded that PSA-NCAM positivity in CSF may be a reliable marker to detect the invasive or metastatic feature of medulloblastoma.
Laboratoire de Biologie Cellulaire II, Faculté de Médecine Saint-Antoine, Paris, France.
C
C
Dubois
D
D
Figarella-Branger
G
G
Rougon
C
C
Rampini
D014408:Biomarkers, Tumor / Q000134:cerebrospinal fluid*; D002528:Cerebellar Neoplasms / Q000134:cerebrospinal fluid* / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008527:Medulloblastoma / Q000134:cerebrospinal fluid* / Q000473:pathology*; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules / Q000134:cerebrospinal fluid*; D012008:Recurrence; D015203:Reproducibility of Results; D012794:Sialic Acids / Q000134:cerebrospinal fluid*
D014408:Biomarkers, Tumor; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule
La NCAM polysialylée du LCR, un marqueur des médulloblastomes invasifs.