P2X7 Receptor Expression in Coexistence of Papillary Thyroid Carcinoma with Hashimoto's Thyroiditis

BACKGROUND This study was aimed at investigating the relation of P2X7 receptor (P2X7R) expression with the clinicopathological features of papillary thyroid carcinoma (PTC) coexisting with Hashimoto's thyroiditis (HT). METHODS We examined 170 patients (84, PTC with HT; 86, PTC without HT). P2X7R expression was examined by immunohistochemical methods. The staining intensity and patterns were evaluated and scored using a semi-quantitative method. RESULTS The PTC with HT group was more likely to contain women and had less extrathyroid extension, lymph node (LN) metastasis, lymphovascular invasion, and recurrence than the PTC without HT group. Patients positive for P2X7R had significantly higher frequencies of lymphovascular invasion, extrathyroid extension, LN metastasis, and absence of HT. As shown by multivariate analysis, the expression of P2X7R was significantly higher if HT was absent and extrathyroid extension was present. In the PTC with HT group, the expression of P2X7R was significantly higher in patients with tumor multifocality, lymphovascular invasion, and extrathyroid extension. In the PTC without HT group, the expression of P2X7R was significantly higher in women and those having tumor multifocality. CONCLUSIONS Coexistence of PTC with HT is associated with good prognostic factors, and P2X7R expression in PTC was correlated with poor prognostic factors and the absence of HT.