CD274 and hereditary clear cell renal cell carcinoma: Using comparative real-time PCR, we observed a 16-fold increase of PD-L1 in flash-frozen GCT compared with PBMCs or with a non–GCT malignancy (renal cell carcinoma; RCC) (Supplemental Figure 3A; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.136773DS1) (PBMCs vs. GCT, P = 0.05; non-GCT malignancy vs. GCT, not significant).