Deregulation of microRNA expression in follicular cell-derived human thyroid carcinomas.

Carcinoma of the thyroid gland is an uncommon cancer, but one of the most frequent malignancies of the endocrine system. Most thyroid cancers are derived from the follicular cell. Follicular carcinoma is considered more malignant than papillary thyroid carcinoma (PTC), and anaplastic thyroid cancer (ATC) is one of the most lethal human cancers. Even though several genetic lesions have been already described in human thyroid cancer, particularly in the papillary histotype, the mechanisms underlying the development of these neoplasias are still far from being completely elucidated. Some years ago several studies were undertaken to analyze the expression of microRNAs (miRNAs) in thyroid carcinoma to evaluate a possible role of their deregulation in the process of carcinogenesis. These studies showed an aberrant miRNA expression profile that distinguishes unequivocally among PTC, ATC and normal thyroid tissue. Here, other than summarize the current findings about miRNA expression in human thyroid carcinomas, we discuss the mechanisms by which miRNA deregulation may play a role in thyroid carcinogenesis, and the possible use of miRNA knowledge in the diagnosis and therapy of thyroid neoplasms.