CXCR4 and nonpapillary renal cell carcinoma: Prior studies have implicated pathways downstream of the VHL and HIF axis, such as CXCR4 and CYTIP or CDCP1 and FYN, being drivers of distant metastases in ccRCC.49,50 Our investigation does not support the metastasis-driving roles of these genes in our models (data not shown).