THERAPY-RELATED CHROMOSOMAL CHANGES AND CYTOGENETIC HETEROGENEITY IN HUMAN GLIOMAS

The karyotypes of 18 primary 'untreated' gliomas, 6 recurrent gliomas treated with radiotherapy and/or chemotherapy and 2 gliomas before and after treatment are described, based on observations using standard c ytogenetic techniques. In comparison to the untreated gliomas there we re relatively consistent chromosome differences in the treated gliomas , including (1) deletions of the long arm of chromosome 7 with breakpo int at q22, possibly induced by alkylating agents, and (2) numerous si ngle cell abnormalities or unrelated clones of structural abnormalitie s, presumably induced by radiotherapy.