ИСТИНА

BACKGROUND. Autoantibody signatures of malignant tumors represent a subset of serum autoantibodies directed against tumor-associated antigens that have been implicated in a number of potential strategies for diagnostics of different tumors. Despite extensive immunoproteomic studies of many malignancies, the autoantibody profile of certain tumors remains largely unknown, and this is the case for differentiated thyroid carcinomas (DTC). To address this issue we carried out immunoproteomic profiling 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. MATERIALS AND METHODS. After informed consent, serum samples were obtained from patients prior to thyroid surgery for PTC (n = 14) or follicular neoplasia (n = 31) as revealed by fine-needle aspiration biopsy. Following histological examination of thyroidectomy specimens, samples were stratified and pooled (5 sera in each pool) according to histological diagnosis to obtain 5 DTC pools and 4 non-cancer pools. Additional control pool was obtained from sera of 5 healthy volunteers. Protein extracts from K1 PTC cells were subjected to 2-dimensional gel-electrophoresis followed by western blotting with 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). RESULTS. All spots that demonstated differential reactivity (i.e. strong reactions in at least 2/5 DTC pools and no/weak reactions in all non-cancer pools) were identified using LC-ESI-MS/MS along with certain representative spots which reactivity was not restricted to cancer and/or was restricted to a single pool. Overall we successfully identified more than 20 immunogenic proteins, 5 of them demonstrating apparent cancer specificity. CONCLUSIONS. We carried out immunoproteomic profiling of PTC cells and identified certain relevant objects that can potentially find use in preoperative differential diagnostics of thyroid tumors in diagnostically challenging cases.