Patterns of FOXE1 Expression in Papillary Thyroid Carcinoma by Immunohistochemistry

Background: FOXE1, a thyroid-specific transcription factor also known as TTF-2, was recently identified as a major genetic risk factor for papillary thyroid carcinoma (PTC). Its role in thyroid carcinogenesis, however, remains unknown. The purpose of the present study was to assess the relationship between the FOXE1 immunohistochemical features and the clinical and genetic characteristics of PTC. Methods: Immunohistochemical staining of FOXE1 was performed in 48 PTC cases. Two single nucleotide polymorphisms immediately inside (rs1867277) or in the vicinity (rs965513) of the FOXE1 gene were genotyped by direct sequencing. Histopathological, clinical, and genetic data were included in statistical analyses. Results: FOXE1 exhibited cytoplasmic overexpression in tumor tissue compared to the normal counterpart (pA) in the 5′ untranslated region of the FOXE1 gene, as well as with pathological characteristics of PTC, suggesting possible FOXE1 involvement in the facilitation of tumor development beginning at an early stage