Expression of papillary thyroid carcinoma-associated molecular markers and their significance in follicular epithelial dysplasia with papillary thyroid carcinoma-like nuclear alterations in Hashimoto's thyroiditis

The aim of this study was to evaluate the expression of papillary thyroid carcinoma (PTC)-associated tumor markers in follicular epithelial dysplasia showing PTC-like nuclear alterations (FED) in Hashimoto's thyroiditis (HT) and to explore the relationship between HT and PTC. In this study, 43 PTC, 18 HT with FED and 16 peritumoral benign thyroid tissues were immunohistochemically analyzed for CK19, galectin-3, HBME-1, CD56, claudin-1 and NGAL expression. Our research revealed that in HT, the expression of CK19, galectin-3, HBME-1, claudin-1 and NGAL was focal and limited to FED, while CD56 was strongly positive in FED and most Hurthle cells. The stain intensity of CK19, claudin-1 and NGAL in FED decreased compared with PTC, but were significantly higher than that in peritumoral benign thyroid tissues (all P < 0.0125). For galectin-3, HBME-1 and CD56, no statistically significant difference was detected between HT and peritumoral benign thyroid tissues (all P > 0.05). In conclusion, In HT, FED might be a precancerous condition closely associated with PTC development as they have overlaps in cytological and immunomarker profiles, indicating that in patients with HT, under prolonged stimuli from chronic inflammation, part of follicular epithelia may show regeneration, hyperplasia, Hurthle cell metaplasia and dysplasia, eventually malignant transformation. Hence, long term follow-up and regular inspection would be necessary for Hashimoto's thyroiditis with FED.