Clonal chromosome abnormalities found in three non-neoplastic proliferative brain lesions

Chromosome analysis was made of brain lesions from three patients which, ac cording to classical histopathological criteria, did not contain tumor cell s. In addition to normal cells, we identified abnormal karyotypes with clon al numerical and structural chromosome alterations in at least two independ ently originated primary cultures from each lesion. Our data suggest that c hromosomal aberrations can exist in vivo in non-neoplastic lesions, Other a bnormalities may be due to genetic instability manifested only in vitro (cu lture artifacts) or may already have been present in brain tissue, reflecti ng previous chromosome damage (as a result of exposure to chemical treatmen t or environmental clastogens).