ABSTRACT
The majority of compounds that induce thyroid neoplasia in rodents do so via an effect on thyroid-stimulating hormone secretion. The majority of thyroid follicular tumors found in humans and animals are benign. Two types of benign tumors may be distinguished: the nodule and the adenoma. Most benign thyroid tumors are multiple and occur in longstanding thyroid disease, where there is thought to have been a deficiency of thyroid hormones over a protracted period of time. The majority of agents that result in the production of thyroid tumors, usually after prolonged administration, interfere with thyroid hormone homeostasis. Few studies have compared the molecular biology of thyroid cancer in humans and animals. Transgenic mice provide a useful tool for studying the effects of putative oncogenes of thyroid epithelial cells in vivo. It is likely that future research into genetic predisposition will throw light on other oncogenes that may be involved in human thyroid carcinogenesis.
