The Relationship between the Expression of MHC Class II Antigens and the Clinical Prognosis of Papillary Thyroid Carcinoma Patients

Abstract

Background: Papillary thyroid carcinoma is among the most curable cancers, but some patients are at high risk for recurrence or even death. MHC antigens are essential molecules for the pathogenesis of carcinoma and also the physiologic immune responses against tumor. However, there is no data about the relationship between the expression of MHC antigens and the clinical prognosis of papillary thyroid carcinoma patients. Methods: We analyzed the relationship between the various prognostic factors and the MHC antigen expression by conducting a retrospective study of 215 patients, who had undergone thyroidectomy for papillary thyroid carcinoma between 1987 and 2003. Results: The expressions of MHC class II antigens were more frequent in papillary thyroid carcinoma than in the other thyroid diseases. Yet there was no statistically significant relationship between most of the clinicopathological factors and the expression of MHC class II antigens in papillary thyroid carcinoma patients. Interestingly, an HLA-DR expression was found in 8 (30.8%) of the 26 patients in the recurrence group and in 13 (76.5%) of the 17 patients in the non-recurrence group, and HLA-DP/DQ immunoreactivity was positive in 10 (38.5%) cases of the recurrence group and in 14 (82.4%) cases of the non-recurrence group. Conclusion: Papillary thyroid carcinoma showed a more frequent expression of MHC Class II antigens. However, the recurred papillary thyroid carcinoma showed a tendency to downregulate the expression of MHC class II antigens. Hence, the molecular mechanism for the expression of MHC class II antigens might have a role in the recurrence of papillary thyroid carcinoma. (J Kor Endocrinol Soc 22:26~34, 2007)