Interestingly, arginine deprivation is becoming a novel and promising clinical strategy for metabolism-based cancer therapy [70, 71].Increased expression of the arginine transporter CAT-1 (SLC7A1) has been reported in high-L-arginine-dependent tumors, such as breast cancer [72], colorectal cancer [73], and hepatocellular carcinoma [74] and CAT-1 silencing decreases the viability of cancer cells and induces apoptosis. The gene discussed is SLC7A1; the disease is breast cancer.