[DNA levels in the cell nuclei of nervous system tumors induced by ethylnitrosourea].

Distribution of DNA in cells of 28 primary ethylnitrosourea-induced tumours of the rat nervous system was studied by the Feulgen cytophotometry method. Out of them 20 had paradiploid DNA quantity, 3 tumours--hypodiploid and 4--hyperdiploid content of DNA. A high heterogeneity of the DNA quantity and the absence of expressed modal class were found only in one case. No correlation is found between the DNA distribution in gliomas and the stage of their malignancy.