CHROMOSOME BREAKPOINT AT 17Q11.2 AND INSERTION OF DNA FROM 3 DIFFERENT CHROMOSOMES IN A GLIOBLASTOMA WITH EXCEPTIONAL GLIAL FIBRILLARY ACIDIC PROTEIN EXPRESSION

A glioblastoma that retained glial fibrillary acidic protein (GFAP) in culture has a break in the long arm of chromosome 17 at band 17q11.2. DNA inserted at this breakpoint came from chromosome bands 3p21, 3q23 , 16q11.2, and 22q11.2. These chromosome fragments were inserted in ba nd 17q11.2 proximal to the neurofibromatosis-1 (NF-1) gene and neu (HE R2; erbB2) oncogene loci. The glioblastoma also contained a reciprocal translocation between 16p12 and 20p12. These structural abnormalities , previously undescribed in gliomas, were demonstrated by high-resolut ion chromosome banding, microdissection, and fluorescence in situ hybr idization (FISH). Numerical changes typical of glioblastoma were prese nt: gain of chromosome 7 and losses of chromosomes 10, 13, and 22. The complex chromosome origin of DNA inserted in this glioma chromosome i s described. The association of two infrequent events in this single g lioblastoma line, this complex insertion and retention of GFAP express ion, is not likely to be a chance occurrence. If raises the possibilit y of an association between the two events.