PRLR and glioblastoma: PrlR was not detected in brain tissues in 11 out of 32 (34%) GBM patients and was detected at grade 1 (<25%) in 5 out of 32 (16%) patients, at grades 2 (>25-50%) and grade 3 (>50-75%) in 2 out of 32 (6%) and at grade 4 (>75%) in 12 out of 32 (38%) patients (Figure 2E).