Next, to examine the molecular mechanism of how AR/ASS1P3 could suppress ASS1 expression in RCC cells, we found that knocking down ASS1P3 decreased ASS1 expression (Fig. 3c, d), and adding ASS1P3 increased ASS1 expression at the protein level, but not at the mRNA level (Fig. 4a), suggesting a potential post-transcriptional regulation that might involve the miRNA(s). This evidence concerns the gene ASS1P3 and renal cell carcinoma.