While both cells lines expressed HIF2α, only UNC-R1 expressed HIF1α (Figure 1B), suggesting that UNC-R2 cells have lost HIF1α expression as is seen in a proportion of ccRCC cell lines and primary tumors and consistent with the notion that HIF1α is potentially a tumor suppressor gene [31]. This evidence concerns the gene HIF1A and nonpapillary renal cell carcinoma.