AMPLIFIED MET GENE LINKED TO DOUBLE MINUTES IN HUMAN GLIOBLASTOMA

The met proto-oncogene was found to be amplified in a human glioblasto ma cell line (T3095) established from a glioblastoma multiform WHO gra de IV. Amplification of epidermal growth factor receptor, transforming growth factor alpha and N-myc which have been described previously in glioblastoma were not observed in T3095. There was, however, an 8-fol d met amplification. Giemsa-stained metaphases of T3095 cells revealed multiple (>5) double minutes (dmins) in the majority of cells. Follow ing xenografting in nude mice there was a significant increase in the number and frequency of dmins. The increase in dmins correlates with t he level of met amplification (50-fold), suggesting localisation of th e amplified met on dmins. Here we report the first case of met amplifi cation in glioblastoma. Correlation between met amplification and extr achromosomal elements (dmins) has not been reported previously.