Heritable lympho-epithelial thymoma resulting from a transgene insertionalmutation

Thymoma is the most common tumor of the anterior-superior mediastinum. We h ave identified a line of transgenic mice which spontaneously and heritably develop thymomas at a very high penetrance. The available data suggest that thymoma formation in these mice results as a consequence of transgene inse rtional mutagenesis, Immune histologic analyses indicate that the thymomas are of epithelial cell origin. Survival studies indicate that tumor progres sion is more aggressive in females as compared to males (73.9 vs 41.7% mort ality at 20 weeks of age, respectively), Fluorescent in situ hybridizations have localized the transgene integration site to the F2-G region of mouse chromosome 2. Translocation encompassing the syntenic region in humans has been implicated in lympho-epithelial thymoma. These animals may constitute a useful resource for the identification of gene(s) which participate in th ymoma progression, as well as a model system for screening anti-thymoma the rapeutic agents.