Decreased expression of catalase mRNA in thyroid anaplastic carcinoma

Background: A decreased expression of glutathione peroxidase mRNA, an antioxidant enzyme, was previously observed in thyroid anaplastic carcinomas. Methods: To clarify the expression of anti oxidant-related enzymes in thyroid anaplastic carcinomas, the expression levels of catalase, copper and zinc superoxide dismutase and manganese superoxide dismutase mRNA in 85 benign and malignant thyroid tissues were measured by means of real-time quantitative reverse transcription-polymerase chain reaction. Results: Decreased expression levels of catalase and copper and zinc superoxide dismutase mRNAs, but not manganese mRNA, were observed in five anaplastic carcinomas compared with normal thyroid tissues and differentiated tumors. Conclusion: These results suggest the possibility that anaplastic carcinoma cells are more likely to suffer damage by oxygen free radicals than normal thyroid cells or differentiated tumor cells.