In grade II gliomas, the MYB translocations (with exon 2 of PCDHGA1 in 5 samples and exon 3 of PCDHGA1 in 4 samples) and the MYBL1 rearrangement (in 6 samples) were technically difficult to prove and validate, which could serve as an indication for differentiating grade I from grade II-III gliomas, which have a potentially more aggressive outcome. This evidence concerns the gene MYBL1 and central nervous system cancer.