EPAS1 and nonpapillary renal cell carcinoma: These results suggest that Axl is not a direct HIF-2α gene target (HIF-1α is not expressed in 786-O cells [34], [35]) Moreover, Axl protein expression was high in ccRCC cell lines with defective VHL protein compared to Caki-2 [36], a ccRCC cell line with papillary RCC characteristic and functional VHL (Fig. 5C).