[Origin and progression of thyroid epithelial tumors: molecular and cellular mechanisms]

Tumours of the thyroid follicular cell have been intensively studied as a model for investigating the molecular genetics of tumour development in epithelial cells. This review summarises the abnormalities of oncogenes and tumour suppressor genes which have been associated with the major sub-types of thyroid tumour. Although inevitably incomplete, the available data demonstrate well how successive genetic abnormalities drive clonal progression. Comparison of follicular and papillary tumours also reveals a fascinating correlation between genotype and pathological behaviour, consistent with a determining influence of the initiating oncogene on the "route" of tumour development. Finally, the emerging clinical implications are discussed.