ASS1 and neoplasm: OCTis primarily expressed in the liver and the renal/intestinal axis; therefore, othertissues cannot readily convert ornithine to arginine31, 32.Many types of tumor cells die in culture media deficient in arginine, whereas normalcells enter quiescence and survive for long periods of time33.Therefore, ASS1 suppression and arginine restriction are promising treatments tohinder metastatic tumor growth.