ИСТИНА

Circulating autoantibodies against a variety of self proteins may represent a useful tool for diagnostics of different pathological conditions, including autoimmune disease and cancer. The autoantigenic repertoire of many malignancies had been extensively studied, while certain tumors are still largely unexplored in this context. Particularly, this is the case for differentiated thyroid carcinomas (DTC). To that end we carried out immunoproteomic analysis of papillary thyroid carcinoma (PTC) cell line K1 using pooled sera obtained from patients with benign and malignant thyroid tumors as well as from healthy volunteers. Protein extracts from K1 cells were subjected to 2-dimensional gel-electrophoresis followed by Western-blot - analysis using sera pools as a source of primary antibodies. Immunoreactive proteins were subsequently identified using liquid chromatography – electrospray ionization tandem mass-spectrometry (LC-ESI-MS/MS). Overall we successfully identified more than 20 immunogenic proteins, 10 of them demonstrating recurrent and apparently cancer-specific reactivities and thus may be regarded as candidate markers for differential diagnostics of thyroid tumors. Further studies using individual sera and recombinant candidates will help to select the most useful signature for preoperative humoral immune response – based discrimination between benign and malignant thyroid lesions.