[Expression of protooncogene bcl-2 in thyroid tumors].

OBJECTIVE: To determine the expression of protooncogene bcl-2 in thyroid tumors and its relationship to the development and prognosis of the tumor. METHODS: 124 cases of thyroid tissues (41 thyroid carcinomas, 53 thyroid adenomas, 20 thyroid tissues adjacent to cancer and 10 normal thyroid tissues) were immunohistochemically stained for bcl-2, by using bcl-2 protein monoclonal antibody. The positive-staining rates in different thyroid tissues were compared statistically. RESULTS: Bcl-2 immunoreactivity was found in thyroid carcinomas (43.9%), thyroid adenomas (22.6%), and thyroid tissues adjacent to cancer (15.0%). The positive-staining rate in thyroid carcinomas was higher than that in thyroid adenomas (P = 0.0439) and that in thyroid tissues adjacent to cancer (P = 0.0430). In thyroid carcinoma, the higher positive-staining rates were found in the cases of undifferentiated carcinoma and follicular carcinoma, as well as in the cases of positive lymph nodes or at tumor stage II and IV. CONCLUSION: The results suggest that the over-expression of bcl-2, a possible prognostic marker of thyroid cancer, may be related to the development of thyroid tumor.