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Deuterated s-RNAs prepared from a medulloblastoma, a glioblastoma and a frontal lobe show a different relative intensity in the 1680 cm–1band. The phenomenon can be related to the frequency in the base pairings; it may depend either on a proportionally different content of t-RNAs and/or on qualitative variations in the primary and secondary structure of the polynucleotides. Irrespective of the kind of variation and its causes, the finding once more proves the existence of chemical differences between neuroectodermal tumors, with an undifferentiated and those with an atypical cellular component.

In unfractioned t-RNAs, prepared from cerebral tumors, the methylated bases were found in a high amount. The increase of them is proportional to the atypia degree, but it is not related to the tumoral growth rate. The results are discussed, in relation to the carcinogenetic hypothesis of the overmethylation.