The detection of a unique antigen associated with papillary thyroid carcinoma

We produced antibodies against a thyroid papillary carcinoma homogenate (PC Ab) and analyzed antigens recognized by this antibody using western blottin g. Fifty-four thyroid tissue specimens and 6 control tissue specimens obtai ned from non-thyroid carcinoma (gastric tissue, colon and liver) were analy zed. Consequently, an antigen of 40 kDa in size was found in 16 of 16 (100% ) of papillary thyroid carcinoma from primary lesions and in 2 of 2 (100%) papillary thyroid carcinoma from metastatic foci, whereas it was not detect ed in thyroid tissue samples from follicular carcinoma, anaplastic carcinom a, follicular adenoma, adenomatous goiter, Graves' disease and normal thyro id tissues. The reactivity of thyroglobulin antiserum (TgAb) to this 40 kDa antigen was tested by western blotting and showed that TgAb did not appear to recognize the 40 kDa antigen. Moreover PCAb, after treatment with Tg, s till reacted with this 40 kDa antigen. Therefore, this 40 kDa antigen might be different from Tg. Furthermore, to inspect the structure of this antige n, the effect of some chemicals and enzymes such as 2-mercaptoethanol, sodi um dodecyl sulfate, ethanol and protease on the reactivity of PCAb to the 4 0 kDa antigen were analyzed. The results of these experiments suggested tha t this 40 kDa antigen may have a peptide structure. To our knowledge, the f inding reported here represents the first demonstration of the protein spec ifically present in papillary thyroid carcinoma. Further investigations sho uld elucidate the characteristics of this antigen and may contribute to def initive diagnosis of thyroid carcinoma as well as improving the understandi ng of the mechanisms involved in developing the thyroid carcinoma. (C) 1999 Elsevier Science B.V. All rights reserved.