Rieznik A. Morphological features of papillary thyroid cancer with biomineralization

The dissertation is devoted to the problem of quality improving of thyroid cancer diagnostics by identifying of morphogenesis features of papillary thyroid cancer (PTC) with biomineralization, the establishment of pathogenic features of carcinogenesis on the assumption of pathological calcification in tumor tissue development. Overall, 1,131 cases of thyroid cancer were investigated. 60 cases of PTC were the basis of morphological, immunohistochemical and physico-chemical studies of dissertation. It was revealed that specific percentage of PTC conducts averages 74.0% in the histological structure of malignant thyroid pathology. The determination frequency of biomineralization in PTC in men is lower than in women. Connection between biomineralization and patients' age was not found. Such types as psammoma bodies, stromal and vascular biomineralization were marked out in PTC biomineralization. Detailed phase and physico-chemical composition of the main forms of pathological biominerals in thyroid gland were established the first time. It was determined that the basis of all types of PTC biomineralization is calcium hydroxyapatite. The value of bax, OPN, VEGF expression in morphogenesis of biomineralized PTC tissue was discovered and the importance of these markers in estimation of malignancy flow was shown. High expression of bax protein and low expression of its antagonist bcl-2 in mineralized tissue of PTC indicate a strengthening of apoptosis in tumor cells. Hyperproduction of OPN by tumor cells can be a possible factor of counteraction to PTC biomineralization. High levels of VEGF expression may indicate a higher level of hypoxia in the tissue of mineralized PTC. The morphogenesis, prognostic and diagnostic value of psammoma bodies in PTC were investigated the first time. Comparing cases of PTC with the presence of metastases, it was indicated that mineralized tissue samples reach larger sizes comparing to cases without calcification manifestation (P<0.02), significantly higher levels of bax (p<0.001), OPN (p<0.008) and VEGF (p<0.012) expression were found in them. In the group of PTC samples without mineralization higher levels of bcl-2 expression (p<0.04) were found. Thus, assessing the influence of biomineralization on PTC course, man can maintain about its favour to protective forces of the body, which is confined in the growth control and in tumor spread. Osteopontin, depositing on the psammoma bodies' surface and combining with calcium compounds, stimulates their consolidation and organization, taking part in the formation of the layered structure. It was shown that the psammoma bodies detection in lymph nodes or in healthy thyroid gland is an important diagnostic feature of hidden PTC. The obtained data can be important criteria in diagnostic of malignant tumors of the thyroid gland and will allow to review the treatment standards of papillary thyroid cancer with biomineralization downward aggressiveness of the treatment process.