Our research is focused on studying lung, breast, thyroid and brain tumors. Experimental studies include the identification of changes in genes structure, expression, and corresponding proteins function, which could be used as molecular markers for the prediction of tumor progression, response to therapy and disease outcome. By comprehensive analysis of PI3K/Akt/mTOR key molecules in the postoperative material of different tumor types and by comparative analysis of the complete genome originating from tumor and normal tissue using DNA profiling method, we managed to identify changes in DNA related to carcinogenesis and to define new candidate genes responsible for the cancer progression and resistance to therapy.