Although Met-1 orthotopic tumors do not readily metastasize in our experience, transwell assays in vitro demonstrated that upregulation of either allele of Arid4b increased tumor cell migration and invasion, consistent with a role of Arid4b in metastatic progression, and cells expressing the DBA allele were significantly more migratory and invasive than cells expressing the AKR allele. The gene discussed is RPS19; the disease is neoplasm.