The role of Fas-mediated apoptosis in thyroid disease

Recent evidence has emphasized the importance of apoptosis in the maintenan ce of tissue homeostasis and the pathogenesis of malignant and immune disea ses. Autoimmune thyroid diseases such as Hashimoto's thyroiditis and Graves ' disease, as well as other autoimmune endocrine diseases, have been associ ated with dysregulation of apoptotic signaling pathways. In particular, dys function of the Fas apoptotic pathway or production of soluble factors incl uding soluble Fas and soluble Fas ligand may be involved in the pathogenesi s of these disorders. On the other hand, malignant thyroid cells may avoid Fas-mediated suicide possibly by expression of inhibitors of apoptosis and evade the immune system by inducing apoptosis on infiltrating lymphocytes. The delicate balance between cell proliferation and cell death through the Fas pathway may also play an important role in the control of thyroid cell mass and goitrogenesis. This review analyzes the current evidence on the ro le of Fas-mediated apoptosis in the pathogenesis of thyroid diseases includ ing Hashimoto's thyroiditis, Graves' disease, thyroid cancer and goiter. Ho wever, the exact mechanisms involved in the regulation of apoptosis in thyr oid disease remain unclear. Further investigation is needed.