SIGIRR and renal cell carcinoma: Similarly, we confirmed the same downregulation of SIGIRR mRNA (protein-coding isoforms 201, 202, 203, 220, 218, 211) and protein levels in all the RCC cell lines in comparison to N2 normal kidney cells, as assessed by RT-PCR and Western blot analysis, respectively [Figures 1E, G where platelets acted as internal positive control (42)].