Experimental models on cell lines for ovarian cancer, hepatocellular carcinoma and melanoma have confirmed that perturbations of urea cycle enzymes enhance malignant cells proliferation, through a detour of the nitrogen substrate toward pyrimidine biosynthesis, using the path of CAD activation (Carbamoyl-phosphate synthetase 2, Aspartate transcarbamylase and Dihydrooratase) [23]. The gene discussed is CAD; the disease is hepatocellular carcinoma.