OVEREXPRESSION AND AMPLIFICATION OF ALPHA-PDGF RECEPTOR GENE LACKING EXONS CODING FOR A PORTION OF THE EXTRACELLULAR REGION IN A MALIGNANT GLIOMA

Overexpression of the alpha-Platelet Derived Growth Factor Receptor (a lpha-PDGF) gene was detected in a case of malignant glioma. This overe xpression was accompanied with amplification of rearranged alpha-PDGF receptor gene. We have isolated a cDNA for the transcript derived from the amplified receptor gene. Characterization of the cDNA revealed a deletion of 243 nucleotides coding for 81 amino acids in the extracell ular region of the receptor. This in-frame deletion removed a part of the immunoglobulin-like domains in the extra.cellular region of the re ceptor. Analysis of the amplified alpha-PDGF receptor gene in the glio ma indicated that exons coding for the 81 amino acids were lost by a g ene deletion. The gene amplification was also detected in macroscopica lly normal cortex adjacent to the glioma from the same patient. Howeve r, the amplified gene in the macroscopically normal cortex had no majo r gene rearrangement. These data suggest that the overproduction of st ructurally altered alpha-PDGF receptor may take part in the onset and the development of malignant glioma.