5hmC Immunohistochemistry: A Predictor of Promoter Mutational Status in Follicular Thyroid Carcinoma?

Telomerase reverse transcriptase () gene aberrancies correlate to adverse prognosis in follicular thyroid carcinoma (FTC). As loss of 5-hydroxymethylcytosine (5hmC) has been associated with promoter mutations in papillary thyroid carcinoma, this study sought to analyze the levels of 5hmC in a cohort of follicular thyroid tumors with available data. A total of 29 tumors (26 FTCs, 2 follicular thyroid tumors of uncertain malignant potential, and 1 oncocytic thyroid carcinoma) with known promoter mutational status and gene expression were assessed for 5hmC immunoreactivity using two antibodies (clones RM236 and 4D9.