AR and glioblastoma: While the AR typically functions as a steroid hormone-activated transcription factor,224 it has been shown in glioblastoma cells that AR activation may also occur in a ligand-independent manner via EGFR signalling.225 AR RNA and protein expression may be induced in as much as 93 and 56% of glioblastoma patients, respectively.226 Thus, the functional significance of AR and its relation to EGFR signalling is of growing interest.