5. Molecular Epidemiology of Thyroid Cancer

Molecular biology studies have greatly enhanced our knowledge of thyroid tumorigenesis, although their impact in clinical practice is still negligible. Most benign and malignant thyroid tumors have a monoclonal origin, suggesting that genetic events are responsible for their occurrence (34). These may involve the activation of oncogenes or the inactivation of tumor-suppressor genes. Several genetic abnormalities (point mutations or gene rearrangements) have been evidenced in human thyroid tumors (review in 14,40,53). Several in vitro and in vivo animal models, including transgenic mice that reproduce the human situations, are also available.