In vivo, an adenovirus-associated JSRV Env expression vector inoculated into immunodeficient mice has been shown to lead to the development of lung adenocarcinoma [108], and a replication-defective JSRV virus only expressing LTR-driven Env upon integration was capable of inducing ovine pulmonary adenocarcinoma lesions in experimentally infected lambs [109]. The gene discussed is ERVW-1; the disease is lung adenocarcinoma.