Iodine and differentiated thyroid cancer: pathogenetic and therapeutic implications.

The purpose of this review is to discuss the various means by which iodine ingestion through dietary intake or therapeutic administration can influence the pathogenesis, prevalence, presentation or outcome of differentiated thyroid cancer (DTC). The relationship between iodine nutrition and DTC pathogenesis is complex, arising from the fundamental observation that anything that stimulates thyroid growth such as TSH, has the potential ability to promote growth and neoplastic transformation in predisposed thyroid follicular cells. One of the other major factors in the pathogenesis of thyroid cancer is previous irradiation. The mechanisms through which events leading to PTC are initiated is uncertain but RET/PTC rearrangements as well as RAS, PAX 8 and PPAR  mutations have been implicated. The sources of irradiation implicated in causing PTC have included the consequences of the nuclear accident at Chernobyl where exposure to radioactive iodine may have been aggravated by the low dietary iodine intake in the affected population.