HBME-1 expression in follicular tumor of the thyroid: an investigation of whether it can be used as a marker to diagnose follicular carcinoma

Background: HBME-1 has been recognized as a useful marker for diagnosing thyroid carcinoma. In this study, we investigated whether it has a diagnostic value for discriminating follicular carcinoma from adenoma. Materials and Methods: We investigated HBME-1 expression in 138 follicular carcinomas, 155 follicular adenomas, 98 adenomatous nodules and 37 papillary carcinomas, using anti-HBME-1 monoclonal antibody. Results: HBME-1 was positive in 60.9% of follicular carcinoma and the incidence was significantly higher (p < 0.0001) than that of follicular adenoma, 30.3%. In adenomatous nodules, only 173% were classified as positive, which was lower even than that of follicular adenoma (p=0.0257). All papillary carcinomas examined were positive for HBME-1. We calculated the positive predictive value of HBME-1 in discriminating follicular carcinoma from adenoma as 64.2%. Conclusion: These results suggest that, although HBME-1 contributes to the diagnosis of papillary carcinoma, it could not be applied in the preoperative diagnosis of follicular carcinoma, for example, using fine-needle aspiration biopsy samples.