title: Expression of glucagon-like Peptide-1 receptor in papillary thyroid carcinoma and its clinicopathologic significance.
abstract: BACKGROUND
  Incretin-based therapies are rapidly becoming one of the main glycemic control strategies in diabetes. Considering the large numbers of papillary thyroid carcinomas (PTCs) and possible effects of glucagon-like peptide-1 (GLP-1) on cell proliferation, the expression of GLP-1 receptor (GLP-1R) in PTC is likely to have clinical significance. We performed this study to evaluate the expression of GLP-1R in PTC and the clinical meaning of GLP-1R expression in PTC.
  
  
  METHODS
  Fifty-six cases of PTC, four cases of medullary thyroid cancer (MTC), seven cases of nodular hyperplasia and 56 normal thyroid tissue samples were selected for immunostaining for GLP-1R. Clinical parameters were obtained by retrospective review of medical records.
  
  
  RESULTS
  Immunohistochemical staining for GLP-1R showed immunoreactivity in 18 of 56 cases of PTC (32.1%). All four cases of MTC exhibited cytoplasmic GLP-1R expression. Nodular hyperplasia exhibited immunoreactivity in two of seven cases (28.6%). All normal thyroid follicular cells showed negative immunoreactivity. In univariable and multivariable analyses, tumor multifocality was negatively correlated with GLP-1R expression. Extrathyroidal extension showed positive association with GLP-1R expression that was almost significant. Sex, age, tumor size, and lymph node metastasis were not significantly associated with GLP-1R expression.
  
  
  CONCLUSIONS
  Some parts of PTC tissues express GLP-1R, and GLP-1R expression in PTC was negatively correlated with tumor multifocality. The long-term influence of pharmacologically increased GLP-1 on thyroid follicular cells and development and progression of tumors originating from thyroid follicular cells should be investigated.
authors.affiliation: Department of Pathology, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan, Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Jung
authors.affiliation: Department of Endocrinology and Metabolism, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan, Korea. mir316@naver.com.
authors.forename: Su Kyoung
authors.initials: SK
authors.lastname: Kwon
keywords: Clinical significance; Glucagon-like peptide-1 receptor; Incretin-based therapy; Thyroid cancer, papillary