[In vitro malignant transformation of fetal hamster brain cells by benzo (a) pyrene].

Hamster embryo brain cells exposed in vitro for 24 hrs. to benzo (a) pyrene and then subcultivated. undergo a morphological transformation. After several passages, transformed cells are capable in most cases of inducing tumors of a special type through intraocular or intracerebral grafting. Histological characterisation of these tumors suggests that they are of glial type. Untreated control brain cells subcultivated for one year, keep their normal characteristics and do not induce tumors when grafted in Hamster.