ASS1 and cancer: Objectively, analysis of public breast cancer datasets revealed a considerably higher arginine level in cancer tissues harboring high expression of EI24 (Fig. 1G), and EI24 linked to the enrichment of arginine_and_proline_metabolism (Fig. 1H), while gene expression data from OncoDB suggested an overall reduction of both ASS1 and EI24 in tumor compared with normal (Supplementary Fig. S1D).