PGF and nonpapillary renal cell carcinoma: Zvirblyte et al. identified five endothelial subpopulations in ccRCC, with the Tumor vasculature 3 subgroup displaying a unique tip cell phenotype, expressing genes like lymphocyte antigen 6 complex locus H (LY6H), placental growth factor (PGF), lysyl oxidase (LOX), carbohydrate sulfotransferase 1(CHST1), and type IV collagen.