Wittchow R, Landas S K
Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City 52242.
Arch Pathol Lab Med. 1991 Oct;115(10):1030-3.
Glial fibrillary acidic protein (GFAP) is a major constituent of glial cytoplasmic intermediate filaments. Glial fibrillary acidic protein expression has been accepted as a marker of astroglial differentiation or origin. However, GFAP expression has been demonstrated in a variety of normal and neoplastic tissues outside the central nervous system, including pleomorphic adenomas, chordomas, bone, and cartilage. It has been postulated that coexpression of GFAP and vimentin in neoplastic myoepithelial cells in pleomorphic adenomas reflects early chondroid differentiation. Glial fibrillary acidic protein expression in chondromyxoid and chordoid tumors was studied in formaldehyde solution-fixed, paraffin-embedded sections of 20 pleomorphic adenomas and 10 chordomas by the immunoperoxidase method with the use of commercially available monoclonal (n = 2) and polyclonal (n = 1) antibodies. All pleomorphic adenomas and chordomas demonstrated expression of GFAP with the use of the polyclonal antibody (Biomeda Corp [Foster City, Calif]). Variable expression of GFAP was present in 90% (18/20) and 70% (14/20) of pleomorphic adenomas, and in 20% (2/10) and 0% of chordomas, with the use of the two monoclonal preparations (Dakopatts [Glostrup, Denmark] and BioGenex Laboratories [San Ramon, Calif]), respectively. Normal brain tissue and eight astrocytomas were used as "controls" to compare staining intensity and quality between the polyclonal and monoclonal anti-GFAP antibodies. Glial fibrillary acidic protein positivity with the polyclonal antibody was more intense than that with either monoclonal antibody despite similar (congruent) distributions of tumor cell types that were stained in control brain and astrocytoma tissues. The GFAP polyclonal antibody was more frequently immunoreactive than the monoclonal antibodies, particularly in cells that exhibited chondroid differentiation. These findings may have practical application in surgical pathology.
胶质纤维酸性蛋白（GFAP）是胶质细胞质中间丝的主要成分。胶质纤维酸性蛋白的表达已被公认为星形胶质细胞分化或起源的标志物。然而，在中枢神经系统以外的多种正常和肿瘤组织中都已证实有GFAP表达，包括多形性腺瘤、脊索瘤、骨和软骨。据推测，多形性腺瘤中肿瘤性肌上皮细胞中GFAP和波形蛋白的共表达反映了早期软骨样分化。采用市售单克隆抗体（n = 2）和多克隆抗体（n = 1），通过免疫过氧化物酶法，对20例多形性腺瘤和10例脊索瘤经甲醛溶液固定、石蜡包埋切片中的软骨黏液样和脊索样肿瘤中的GFAP表达进行了研究。使用多克隆抗体（Biomeda公司[加利福尼亚州福斯特城]）时，所有多形性腺瘤和脊索瘤均显示GFAP表达。使用两种单克隆制剂（Dakopatts公司[丹麦格罗斯特鲁普]和BioGenex实验室[加利福尼亚州圣拉蒙]）时，分别有90%（18/20）和70%（14/20）的多形性腺瘤以及20%（2/10）和0%的脊索瘤存在GFAP的可变表达。正常脑组织和8例星形细胞瘤用作“对照”，以比较多克隆和单克隆抗GFAP抗体之间的染色强度和质量。尽管对照脑和星形细胞瘤组织中染色的肿瘤细胞类型分布相似（一致），但多克隆抗体的GFAP阳性比任何一种单克隆抗体都更强。GFAP多克隆抗体比单克隆抗体更频繁地出现免疫反应，特别是在表现出软骨样分化的细胞中。这些发现可能在外科病理学中有实际应用。
