Investigation of DNA topoisomerase I as an autoantigen at the thyroid cancer

The data concerning DNA-Topoisomerase I (Topo-I) from human placenta as an autoantigen at the thyroid cancer are presented. A new effective scheme of the Topo-I purification using the High-Trap columns is described, as well as the enzyme physico-chemical properties and its immunoreactivity in the ELJSA and immunoblotting. It was shown that 46 % of the sera from patients suffering the thyroid cancer were immunoreactive against Topo-I, 36 % of autoantibodies from thyroid cancer patients sera recognized sequential determinants on the Topo-I molecule. The highest levels of immunoreacivity were observed in the sera of thyroid cancer patients accompanied by autoimmune thyroiditis. We suggest a possible linkage between the autoimmune processes and malignization of the thyroid gland cells.