Surasawadee Ausavarat
Mahidol University, Thailand
Title: Efficacy of TSHR mRNA as a tumor marker in the follow-up of differentiated thyroid cancer
Biography
Biography: Surasawadee Ausavarat
Abstract
Objectives: Measurement of serum thyroglobulin (sTg) by immunoassay is used as a tumor marker for differentiated thyroid cancer (DTC), however, the possible interference of endogenous anti-thyroglobulin antibodies (TgAb) and low sensitivity during thyroid hormone suppression may limit its clinical usefulness. Therefore, many researchers have evaluated the efficacy of thyroid-transcripts by molecular assay instead. Here we investigated the efficacy of thyroid-stimulating hormone receptor (TSHR) mRNA during thyroid hormone suppression especially in TgAb-positive patients.
Methods: We studied 160 patients with differentiated thyroid cancer and 27 normal subjects without history of thyroid disease. All patients had undergone near-total thyroidectomy and radioactive iodine ablation. Of the 160 patients, 49 (30.6%) were classified as in-remission, 111 patients (69.4%) were disease-persistence, of which, 27 patients (24.3%) were TgAb-positive. Quantification of TSHR mRNA was performed using real-time PCR.
Results: Median TSHR mRNA level of in-remission group was significantly different from disease-persistence in TgAb-positive patients, particularly in distant metastasis patients. Analysis of TSHR mRNA at 2.00 pg Eq/µg total RN enabled us to discriminate between remission and disease-persistence at sensitivity of 88.9% and specificity of 42.9%. However, there is no correlation between level of TSHR mRNA and sTg or TSHR mRNA and TSH in all groups.
Conclusion: We demonstrated that TSHR mRNA has greater sensitivity in prediction of disease-persistence in TgAb-positive patients than sTg during thyroid hormone suppression. Further study should emphasize the cost-effectiveness of routine usage of the assay in clinical practice.