VHL and renal cell carcinoma: To investigate the value of TfR1 as a predictive marker of the suitability of ART for the treatment of RCC, we next examined TfR1 expression levels in various human RCC cell lines [VHL wild-type RCC cell lines = Caki-1 and SN12C-GFP-SRLu2; VHL-deficient (mutated or hypermethylated) RCC cell lines = A498, 769-P, and 786-O] and normal renal cortical epithelial cells (RCECs) (Figure 2C).