In a human esophageal squamous cell carcinoma xenograft model or in a syngenic murine model of mammary gland tumorigenesis, tumor cells overexpressing Csta demonstrate a reduced capacity to form lung or bone metastasis respectively, suggesting that Cystatin A may act as a tumor suppressor within these contexts [15], [16]. The gene discussed is CSTA; the disease is esophageal squamous cell carcinoma.