KLF5 and nonpapillary renal cell carcinoma: It is well known that inactivation of the tumor suppressor gene Von Hippel-Lindau (VHL), including deletion, mutation and hypermethylation, is an archetypical tumor-initiating event in ccRCC, which leads to constitutive activation HIF-α that promotes tumorigenesis.26 To investigate whether VHL loss resulted in KLF5 suppression in ccRCC, VHL expression was detected in ccRCCs and HEK-293T cells.