PRF1 and renal cell carcinoma: Prior studies of RCC have described molecular subgroups with gene expression signatures that reflect activation of key molecular pathways, including T effector (comprising CD274, CD8A, EOMES, IFNG, and PRF1) and angiogenic (comprising ANGPTL4, CD34, ESM1, KDR, KDR, PECAM1, and VEGFA) gene sets, and these subgroups were further associated with differential outcomes to therapy (17, 20).