The expressions of β-catenin, c-myc and cyclin D1 in thymoma induced by ionizing radiation

Wnt / β-catenin signaling pathway play an important role in the development of tumor. Here we try to study its role in tumor through investigating the expressions of β-catenin, c-myc and cyclin D1 in thymic lymphomas of mice induced by ionizing radiation. The mouse model of thymic lymphomas induced by irradiation was made according to the Kaplan´ method. The mice were killed and the thymus were removed out in 3 and 6 months. The characteristics of the thymus structure was observated by histopathology and the protein expression positions of β-catenin, c-myc and cyclin D1 were detected by immunohistochemistry. The pre-cancerous changes and lymphoma were seen in the thymus 3 and 6 months later. The ectopic expression rates of β-catenin in the nucleus and the cytoplasm of precancerous lesions and thymoma were 38.5% (5/13) and 53.0% (9/17). The positive expression rate of c-myc and cyclinD1 in precancerous lesions was respectively 46.2% (6/13) and 30.8% (4/13). Their positive expression rate in lymphoma was 64.7% (11/17) and 41.2% (7/17). These results indicate that wnt signaling pathway involved in the occurrence of thymoma induced by irradiation.