Epigenetic modifications in human thyroid cancer

Thyroid carcinoma is the most common endocrine malignancy of the endocrine organs, and its incidence rate has steadily increased over the last decade. Over 95% of thyroid carcinoma is derived from follicular cells that have a spectrum of differentiation to the most invasive malignancy. The molecular pathogenesis of thyroid cancer remains to be clarified, although activating the RET, RAS and BRAF oncogenes have been well characterized. Increasing evidence from previous studies demonstrates that acquired epigenetic abnormalities participating with genetic alteration results in altered patterns of gene expression/function. Aberrant DNA methylation has been established in the CpG regions and microRNAs (miRNAs) expression profile recognized in cancer development. In the present review, a literature review was performed using MEDLINE and PubMed with the terms 'epigenetic patterns in thyroid cancer [or papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), medullary thyroid cancer (MTC), anaplastic thyroid cancer (ATC)]', 'DNA methylation in thyroid cancer (or PTC, FTC, MTC, ATC)', 'miRNA expression in thyroid cancer (or PTC, FTC, MTC, ATC)', 'epigenetic patterns in cancer' and the current understanding of epigenetic patterns in thyroid cancer was discussed.