Identification of tumor-related proteins by proteomic analysis of cerebrospinal fluid from patients with primary brain tumors.

Cerebrospinal fluid (CSF) has been rediscovered in the post-genomic era as a great source of potential protein biomarkers for various diseases. The source allows rapid screening, low sample consumption, and accurate protein identification by proteomic technology. In the present study, we identified 2 candidate tumor-related proteins, N-myc oncoprotein and low-molecular weight caldesmon (l-CaD), in CSF samples of patients with primary brain tumors by using 2-dimensional polyacrylamide gel electrophoresis (2D PAGE), followed by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis. N-myc and l-CaD were related to tumor cell nuclei and blood vessels, respectively, in tissue sections of the tumor biopsies taken from the same patients from whom CSF was processed. N-myc oncoprotein and l-CaD have not been detected in CSF before. The practical value of these proteins as possible tumor markers, prognosticators, or their utility in monitoring response to chemotherapy is currently a subject of investigation. It is concluded that the combination of 2D PAGE and MALDI-TOF-MS is successful as an unbiased global screening tool for CSF.