THE ROLE OF GROWTH-FACTORS IN PROLIFERATION AND INVASION OF THYROID-CANCER

A growing literature has established the close association between tum or progression and growth regulatory aberrations in cancer cells. Most studies have focused on the phenomenon, that advanced tumors or metas tases have lost the sensitivity to growth inhibitors. Metastasis are t he primary cause of death in patients with differentiated thyroid canc er. Proliferation and differentiation of the thyroid was supposed to b e under the major control of only a single hormone (thyroid stimulatin g hormone). However, we and others have shown that a complex network o f various growth factors regulates growth and invasion of thyroid canc er cells. Our findings highlight two aberrations of growth regulation which may favour progression of malignancy and acquisition of metastat ic competence: i) resistence to growth factor inhibitors and ii) growt h autonomy of metastatic thyroid cancer cells.