GST-ARG1 exhibited a very potent inhibitory activity, with an IC80 (80% inhibitory concentration) of less than 400 mU/ml, in some human cell lines, namely: pancreatic cancer BxPC-3 (84.9 mU/ml), breast cancer MCF7 (163.5 mU/ml), cervical cancer HeLa (373.2 mU/ml), and melanoma SK-MEL-5 (378.2 mU/ml) (Supplementary Table S1). The gene discussed is ARG1; the disease is melanoma.