In GBM tissue, compared to low-grade gliomas, or non-tumour control tissue, De Jesús et al. revealed reduced expression of CB1R [106], Schley et al. determined that CBR1 expression remained unchanged [107], and Wu et al. [108] and Ciaglia et al. [109] found CBR1 expression to be elevated (reviewed in [110]). This evidence concerns the gene CBR1 and central nervous system cancer.