Молекулярні механізми утворення метастазів. Маркери метастазування при карциномах щитоподібної залози (огляд літератури)

Metastases account for 90% of deaths from solid tumors. The metastasis process involves the exit of cancer cells from the primary tumor, their transition into the circulatory or other transport system, and finally, colonization and proliferation in a distant organ. The review describes the process of metastatic cell development due to genetic, epigenetic, positional changes, and signals from surrounding cells. During the epithelial-mesenchymal transition, the tumor cells partially and temporarily dedifferentiate, change their shape towards an unpolarized, mobile, spindle-shaped cell. This transition makes it possible to establish gene expression and acquire the stem cell phenotype. The mechanisms of mobility and invasiveness of tumor cells, the processes of intravasation, transportation, and homing are also considered. Considerable attention is paid to the formation of a pre-metastatic niche, which is characterized by immunosuppression, inflammatory processes, intense angiogenesis, vascular permeabilization, active lymphangiogenesis, specific organotropism and high reprogramming efficiency. The process of colonization of a metastatic niche by tumor cells, the participation of cells of the immune system, other blood cells, bone marrow progenitors, exosomes, which are formed in the environment of a primary tumor, metabolic enzymes and pro-inflammatory cytokines, are analyzed in detail. The emphasis is made on the metastatic processes in the thyroid tumors. The main markers of metastasis for thyroid carcinomas for allstages of the metastatic cascade are presented and analyzed. Suppressors of metastasis have been described, the effect of the tumor microenvironment, the importance of inflammatory processes and other pathologies in the occurrence and progression of thyroid carcinomas have been assessed.