VHL and nonpapillary renal cell carcinoma: We analyzed tumor and healthy tissues from 43 ccRCC patients after radical nephrectomy and cultured 786-O (biallelic VHL inactivation) and Caki-1 (wild-type VHL) cells in normal (21% O2) and low oxygen (3% O2) with 10% and 2% fetal bovine serum (FBS).