Experimental Animal Division

 　The Drs (downregulated by v-src) gene is originally found as a novel suppressor of v-src transformation. The Drs gene expresses in most normal tissues, however the expression is completely downregulated in a variety of cancer cell lines and tissues. It has been shown that malignant tumors such as lymphomas, lung adenocarcinomas and hepatomas were generated in about 30% of the Drs KO mice between 7 and 12 months. The Drs KO embryonic fibroblasts also showed enhanced sensitivity to transformation by viral oncogenes. Reintroduction of Drs gene into a tumor cell line derived from the tumor of the Drs KO mouse suppresses tumorigenesis and enhances caspase-mediated apoptosis.