Glial fibrillary acidic protein in tumor types with cartilaginous differentiation.
Glial fibrillary acidic protein (GFAP) is a member of the intermediary filament protein family. It is an important component of astrocytes and a known diagnostic marker of glial differentiation. GFAP is expressed in other neural tumors and pleomorphic adenoma and, less frequently, in cartilage tumors, chordomas, and soft tissue myoepitheliomas. The aim of this study was to evaluate the role of GFAP and its reliability in nonglial tumors as an immunohistochemical marker. We evaluated GFAP gene and protein expression using Q-PCR and immunohistochemistry, respectively, in 81 and 387 cases of soft tissue, bone tumors, and salivary pleomorphic adenomas. Immunohistochemistry staining for GFAP was observed in all osteosarcomas (8 cases), all pleomorphic adenomas (7 cases), in 5 of 6 soft tissue myoepitheliomas, and in 21 of 76 chondrosarcomas. By Q-PCR, GFAP was highly expressed in pleomorphic adenomas and, to a lesser extent, chondrosarcomas, soft tissue myoepitheliomas, and chondroblastic osteosarcomas. The results that we obtained by immunohistochemistry and Q-PCR were well correlated. GFAP is a potential marker for tumors with cartilaginous differentiation, supported by evidence that GFAP is expressed in certain cases of myoepithelial tumors by immunohistochemistry, including soft tissue myoepitheliomas, which are related to cartilaginous differentiation. These findings contribute significantly to the diagnosis of soft tissue myoepitheliomas with cartilaginous differentiation and chondroblastic osteosarcoma in mesenchymal tumors.
Santos
Giscle Caravina
GC
Department of Pathology, Hospital do Cancer de Barretos, Barretos, SP, Brazil.
Carvalho
Kátia Candido
KC
Falzoni
Roberto
R
Simoes
Ana Carolina Q
AC
Rocha
Rafael Malagoli
RM
Lopes
Ademar
A
Vassallo
Jose
J
Reis
Luiz Fernando Lima
LF
Soares
Fernando Augusto
FA
da Cunha
Isabela Werneck
IW
D008949:Adenoma, Pleomorphic / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001859:Bone Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D002356:Cartilage / Q000737:chemistry* / Q000473:pathology; D002454:Cell Differentiation; D015972:Gene Expression Regulation, Neoplastic; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D009208:Myoepithelioma / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012468:Salivary Gland Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000473:pathology
D014408:Biomarkers, Tumor; D005904:Glial Fibrillary Acidic Protein