ISG20 and nonpapillary renal cell carcinoma: Then we measured the expression of selected IFN-responsive genes with RT-PCR, and found that the transcriptional changes in IL6, ISG20, IL8, ARPC4, GAS6, and STMN3 were consistent (Figure 3D). To ensure that our observation is not confined to just one cell line, we performed similar experiments in Ren-02 cells, another VHL-/- ccRCC cell line.