Assessment of brain tumors in the offspring at 5 months of age showed the presence of mixed gliomas (astrocytomas/oligodendrogliomas) in 70% of the ENU + saline group of rats and only in 30% of the ENU + LY341495 group.<h4>Conclusion</h4>Tumors in both groups of rats showed a moderate/high expression of the astrocyte marker, GFAP, and the oligodendrocyte marker, OLIG-2, and a low expression of the proliferation marker, Ki-67. This evidence concerns the gene MKI67 and central nervous system cancer.