[Cytophotometric determination of DNA concentration in the cells of experimental brain tumors. II. Primary tumors of rat cerebellum induced by 9, 10-dimethyl-1, 2-benzanthracene].

The Feulgen-DNA cytophotometry was applied for studies of 31 rat cerebellum tumors induced by 9, 10-dimetyl-1,2-bensantracene. Most of these gliomas (22) were astrocytomas of different grades of malignancy. The histological diagnosis of other tumors was: glioblastoma -- 4, oligoastrocytoma -- 2, oligodendroglioma -- 1, gliosarcoma 1. The majority cells of 26 tumors had diploid or paradiploid DNA quantity, 4 tumors (1 astrocytoma, 3 dedifferentiated astroyctomas) had triploid modal classes. The tetraploid modal class and a large number of polyploid cells were found only once for glioblastoma multiforme. A supposition was made that drastic changes of ploidy could arise for the second time during the process of tumor evolution. The authors failed to show any exact differences in the ploidy of gliomas in rats with athyreosis or hyperthyreosis, and in the ploidy of somatic cells in control animals.