HIF1A and nonpapillary renal cell carcinoma: Consistent with the above findings that HIFs do not contribute to the enhanced cytotoxicity of anthracyclines in VHL-deficient ccRCC cells, the ALDH2 protein levels were also not affected by HIF-1α and HIF-2α silencing in RCC4 cells and 786-O cells (Fig. 6e,f).