Обобщены данные литературы, свидетельствующие о том, что стойкое снижение активности ГАМК-ергической системы может быть одной из составляющих механизма активации канцерогенеза. Кроме того, в собственных исследованиях установлено, что в ткани папиллярной карциномы уровень ГАМК значительно ниже, чем в противоположной доле без признаков опухолевого роста. В то же время в ткани щитовидной железы при выявлении в ней патоморфологических признаков опухолевого роста концентрация ГАМК значительно выше, чем в таковой без признаков малигнизации.

Aim - the aim of this study was to evaluate the frequency of existence of thyroid extratumoral normo- and microfollicular tissue in patients with thyroid carcinoma and peculiarities of apoptosis in mentioned tissue. Using samples of normo- and microfollicular thyroid tissue it was determined the content of fragmented DNA and intensity of stimulated internucleosomal DNA fragmentation; activities of caspase-3 and cysteine lysosomal cathepsins. It was found that normofollicular tissue is observed more often in patients with nodal euthyroid goiter but microfollicular tissue is more common for patients with carcinoma. Extratumoral microfollicular tissue was found in the thyroid of patients above 50 years old mostly, and more rarely in young ones. The fragmented DNA concentration in microfollicular tissue was lower by a factor of 3,5 and intensity of stimulated internucleosomal DNA fragmentation was also decreased. Activity both of cathepsin B in lisosomes and caspase-3in lysates of such tissue was also decreased. Conclusions: the decrease of intensity of spontaneous apoptosis and the absence of its modulation/induction following proapoptotic factors in extratumoral microfollicular thyroid tissue may be considered as a respond of the thyroid gland tissue to an existence of carcinoma.

Aim - to determine biological and clinical features of papillary and follicular thyroid carcinomas associated or not associated with chronic thyroiditis. The study was conducted by retrospective analy sis of medical histories of 2,459 patients with thyroid cancer. Tumor size, its category according to the TNM system, multi-focal properties of tumor growth, carcinoma invasiveness, as well as disease stage, rates of relapses and metastasis, and also cumulative survival rates were analyzed. The tumor size in patients with papillary or follicular carcinoma associated with thyroiditis was smaller compared to the patients without thyroiditis. In the first case, the invasion frequency into extrathyroid structure and into the capsule was also lower. Multi-focal growth of both carcinoma types was registered more frequently in the presence of thyroiditis. The frequency of papillary carcinoma metastasis to lateral cervical lymph nodes was lower in the presence of thyroiditis, the frequency being equal for metastasis into lymph nodes of the VI lymph outflow zone in both groups of patients (with and without thyroiditis). In the presence of thyroiditis, the frequency of distant papillary carcinoma metastasis was decreased, no metastases were detected in patients with follicular carcinoma. In the group of patients with papillary carcinoma there was found no relation between the presence of thyroiditis and disease stage, relapse rates, and mortality levels; however, the risk of follicular carcinoma relapse was significantly lower in patients with thyroiditis. Conclusions: the presence of chronic thyroiditis in papillary carcinoma patients showed a certain positive impact on the course of the disease, in particular, primary tumor growth, invasion, and metastasis. Such effect is even more expressed in the patients with follicular thyroid carcinoma.