GPR55 and glioblastoma: We analysed CNR1, GPR55, and TRPV1 mRNA levels in tissue samples from normal non-malignant brain tissues (n = 16) and neoplastic brain tissues: low-grade (WHO grades I and II) glioma (n = 17), WHO grade IV glioma (wild-type GBM) (n = 89), and recurrent GBM (n = 6), as well as from primary GBM cells (n = 10) and GSCs (n = 6) isolated from patient tumour samples.