The association between sex steroid receptors and brain tumors was first described in 1983 [4], but in contrast to the well-established oncogenic role played by androgen receptor (AR) in prostate cancer (reviewed in [5]) and the growing evidence of its role in breast cancer (reviewed in [6]), the expression and significance of AR in GBM is controversial and poorly studied. The gene discussed is AR; the disease is Familial prostate cancer.