VHL and nonpapillary renal cell carcinoma: Zebrafish vhl mutants display pronephric abnormalities from soon after the nascent kidney becomes functional., Interestingly, the cells of the pronephros display a phenotype reminiscent of the clear cell phenotype seen in clear cell Renal Cell Carcinoma (ccRCC), a disease caused by loss of heterozygosity of VHL, but do not develop tumours or cysts [42, 44, 45].