STABLE RADIOBIOLOGICAL FEATURES IN A GENETICALLY UNSTABLE GLIOBLASTOMA CELL-LINE

In a human glioblastoma (grade IV) cell line, A7, the change in chromo some number, growth characteristics, radiosensitivity and DNA-repair c apacity were determined during continuous culture over approximately 1 300 generations. The median chromosome number fell from 101 to 85 whil e a remarkable variability was retained. The net population doubling t ime shortened from 21 to 16 h but no alterations were detected either in radiosensitivity or DNA-repair capacity, as measured by colony and plasmid-reconstitution assays respectively. Reviewing radiosensitivity data from the literature, it is considered that the relative radiores istance of glioblastomas might be inherited from the normal tissue fro m which they are derived.