Protein patterns in various malignant human brain tumors by two-dimensional gel electrophoresis

Two-dimensional gel electrophoresis with silver staining was used to study protein patterns in various malignant human brain tumors obtained at surgery. These samples included 20 high-grade astrocytomas (anaplastic astrocytomas and glioblastomas), one low-grade astrocytoma, six juvenile astrocytomas, four ependymomas, and five medulloblastomas. Histological correlates of the sampled tissue were carefully established prior to micropunch sampling. The molecular weight range of these gels was 14,000 to 100,000, and the isoelectric points ranged from 4.7 to 7.0. Proteins that have been identified include albumin, actin, tubulin, glial fibrillary acidic protein, vimentin, glutamic oxaloacetic transaminase, neuron-specific enolase, and the beta-subunit of the guanine nucleotide regulatory proteins. Each type of tumor was found to have a characteristic protein profile that set it apart from the other tumors studied. By providing a convenient tool for the display of a wide spectrum of tumor markers in a single study, two-dimensional gel electrophoresis protein profiles may be useful as diagnostic and prognostic adjuncts. Furthermore, several protein spots that were not noted in normal human cortex were identified in the various tumor gels. Antibodies can be raised against some of these tumor-associated proteins, and their further characterization could provide valuable insights into the biology of these tumors.