Tiroid Kanseri Tanısında TSH Reseptör ve E- Kaderin Gen Metilasyonunun Sitolojik ve Histopatolojik Olarak Araştırılması

Abstract

It is determined by the researchers that tumor supresor genes are found in methylated forms in the cancer onkogenesis of thyroid malignancies. TSH receptor and ECAD receptor genes can be classifed as thyroid specific genes. In this experimental study the methylation status of these thyroid specific genes and their clinical use in the differantiation of benign and malign thyroid nodules are investigated. MATERIAL METHOD: Of the 4355 patients with nodular goiter, who have been treated between 2007 and 2011, 76 patients were selected. Deoxyribonucleic acids (DNA) were isolated from the cytology specimens obtained by fine needle aspiration biyopsy. After isolation of the DNAs, the methylation status of TSHr and ECAD receptor promoter regions were investigated by methylation specific polymerase chain reaction (M- PCR). Also the relation between methylation status of the genes and gender, age, size of the nodules and blood thyroglobulin levels of the patients were studied. RESULTS: The ratio of methylated TSHr was found 87,5% of patients with papillary thyroid cancer, 58,1% of patients with have cytological features of atypia of undetermined significance, 41,7% of patients with suspected cytological features for a follicular neoplasm and 47,1% of patients with benign nodular guatr (p< 0.05). CONCLUSION: The ratio of TSHr methylation in papillary thyroid carcinoma group adduced that TSHr methylation status can be utilised as a tumor marker for papillary cancer. It is shown that the methylation status of TSHr genes have no role in determining the malignant potential for the nodules which are cytologically classified as atypia of undetermined significance and for the nodules which are cytologically found to be suspicious for a follicular neoplasm. There was no statistical discrepancy between TSHr methylation status and gender, age, size of the nodules and blood thyroglobulin levels of the patients. TSHr of patients who with poor prognostic factors for papillary thyroid cancer (9 patient) were all in methylated form. This study shows that more clinical studies are needed for searching TSHr metyhlation as a prognostic factor. No significant results were determined about the ECAD receptor gene methylation. Acording to our knowledge this study is the first try in the medical literature which searches the TSHr methylation status from cytologically derived DNA.