Expression of Arginase1 (Arg1) and Arginosuccinate lyase (Asl) was elevated by 4T1 breast cancer (Fig. 5c) while the mRNA levels of Ornithine carbamoyltransferase (Otc) and Arginosuccinate synthase 1 (Ass1) were reduced. The gene discussed is ASL; the disease is breast carcinoma.