In medium containing arginine at a physiological concentration resembling plasma35 or the tumor microenvironment (TME)36 (Figure S3D), ARG1 or AGMAT expression markedly reduced clonogenic growth of SNU-449 cells, while ARG1/AGMAT co-expression arrested growth (Figures 3B, 3C, and S3E). The gene discussed is AGMAT; the disease is neoplasm.