KDR and renal cell carcinoma: The incidence rate of clear cell renal cell carcinoma (ccRCC) accounts for 75–80% of RCC [3, 4]. Although the targeted therapies such as targeting of VEGFR/PDGFR tyrosine kinases and mTOR pathway, and the immunotherapies (pembrolizumab, ipilumumab, nivolumab) significantly improved the prognosis of metastatic ccRCC [5–7], 30% of RCC patients with metastasis showed a primary resistance to the molecular targeted drugs [6].