CD274 and glioblastoma: Using a defined predictive cut point of >10% for tumour proportion score, identified as a cut-point for PD-L1 IHC companion diagnostic assays in relation to anti-PD-L1/anti PD-1 directed therapies [23], PD-L1 expression levels were significantly raised in 27.3% of glioblastomas with 12.7% of cases having a tumour proportion score of >50% (S4 Fig).