ASS1 and nonpapillary renal cell carcinoma: However, in this different metastatic model, ASS1 mRNA is marginally upregulated in metastatic OS-LM1 compared to OS-RC-2 (Supplementary Fig. 8e) even though ASS1 was strongly suppressed in both ccRCC cells when compared to HK2 cells at the protein level (Supplementary Fig. 8f).