Amplification of the platelet-derived growth factor receptor-A (PDGFRA) gene occurs in oligodendrogliomas with grade IV anaplastic features

Activation of the platelet-derived growth factor (PDGF) signaling system ha s been implicated in the development and malignant progression of diffuse g liomas. Overexpression of PDGF system components, particularly the alpha su btype receptor (PDGFRA), is common in glial tumors, and PDGFRA gene amplifi cation has been reported in glioblastomas. In order to address the incidenc e of PDGFRA gene amplification in a broad set of diffuse gliomas, we used S outhern and fluorescence in situ hybridization (FISH) analyses to examine 1 67 astrocytic gliomas (20 grade III and 147 grade IV), 41 anaplastic oligod endrogliomas, and 29 anaplastic oligoastrocytomas. PDGFRA gene amplificatio n was identified in 4 anaplastic oligodendrogliomas and in a single case of anaplastic oligoastrocytoma, but in none of the malignant astrocytomas. Ea ch of the 5 tumors with PDGFRA amplification displayed features generally a ssociated with grade IV malignancy in astrocytic tumors. Consequently, our data indicate that this gene alteration is restricted to tumors having olig odendroglial differentiation and highly anaplastic features.