DETERMINATION OF SURVIVIN AND PROTEIN KINASE AKT IN PAPILLARY THYROID CARCINOMA AND METASTASIS TISSUES

Background. Survivin is a member of Inhibitors of Apoptosis proteins (IAP) family. It is expressed in actively proliferating cells, and is upregulated in most cancers; consequently, it has received significant attention as a potential oncotherapeutic target. Akt is a central signalling molecule of the phosphoinositide 3-kinase (PI3K)/Akt signalling pathway. It is a serine/threonine-specific protein kinase and involved in apoptosis, proliferation, transcription and migration. Aberrant activation of this pathway has been identified in a wide range of cancers and thyroid as well. The aim of the study was to compare the expression of survivin and activation of protein kinase Akt in the tissues of patients with goiter, multinodular goiter (MNG), papillary thyroid carcinoma (PTC) with and without metastasis (Mts) to the lymph nodes.Materials and methods. Postoperative specimens of tumor tissue, metastasis (Mts), benign neoplasms (goiters) and conditionally normal tissue were used for the studies. The expression of survivin mRNA was determined using real-time polymerase chain reaction (qPCR). The expression of Akt was determined using Western-blotting.Results. The obtained data indicate that the expression of the survivin mRNA in PTC tissue and Mts significantly exceeds the level of its expression in conditionally normal (more than 4.5 times) and goiter tissues. The expression of survivin in PTC without metastasis more than three times lower compared to PTC with metastasis. In metastasis the level of IAP mRNA expression is lower than in the primary tumor. The expression of the phosphorylated (activated) form of Akt in PTC tissue and Mts significantly higher than level of its expression in conditionally normal tissue. The level of Akt in Mts is almost 4 times higher than in the primary tumor and almost 8 times higher than in the conditionally normal tissue.Сonclusions. Thus, an increased survivin mRNA expression in papillary thyroid carcinoma may be marker of metastasis formation. It can also be used to differentiate between benign and malignant thyroid lesions. The level of the phosphorylated (activated) form of Akt is especially high in metastasis.