The reason for this is not known, but since the J3TBG glioma cell line is known to behave aggressively, there might be a contribution of more necrotic tumor cells generated in Group C than in the treatment groups (CBD, RT, CBD + RT groups), resulting in fewer percentage of Ki-67-positive cells and fewer number of positive cells (cells/μm2), as shown in Figure 3. This evidence concerns the gene MKI67 and central nervous system cancer.