cfDNA Promoter Methylation Quantification of DNMT1 and MGMT Genes in Papillary Thyroid Cancer Tissues

Background and Aim: Endocrine tumors are endocrine system relatedmalignancies like thyroid that is the most common type with mountingtrends over the last three decades worldwide. Papillary thyroid cancer(PTC) is making four-fifths of all thyroid cancers. Finding some detectionmarkers in order to discriminate malignant from the benign one beforemetastasis could be really important for thyroid cancer patients andclinicians. Epigenetic silencing through aberrant DNA methylation oftumor suppressor genes linked to a variety of devastating consequencesof human cancer. Two DNA methyltransferases DNMT1 and MGMTwere selected as the key epigenome writers. We determined the quantityof methylation in twelve candidate promoter regions of four tumorsuppressor genes using the Methylation-sensitive high-resolution melting(MS-HRM) assay.Methods: Fresh frozen tissues and blood of 35 PTC patients and 34 goiterpatients were collected after surgery. DNA was extracted from plasmaand tissue using QIAGEN Kit according to the manufacturer’s protocol.DNA purity and quantity were determined using a Thermo Scientific™NanoDrop™ spectrophotometers 2000c spectrophotometer and thenstored at -80°C. For bisulfite treatment DNA from each sample weretreated with sodium bisulfite conversion kit. The MS-HRM analyses wererun based on the three main steps of Holding, Cycling, and Melt curve.Statistical analysis was done by the Statistical Package for the SocialSciences (SPSS) version 16.0 and P <0.05 was considered statisticallysignificant.Results: Promoter methylation of MGMT and DNMT1genes hasmeaningful differences between PTC cases and goiter controls.Conclusion: Among the different selected promoter region of twoselected genes the, MGMT (a), MGMT (c), MGMT (d), and DNMT1 (b)methylation status were meaningfully different between PTC cases andcontrols. Our result suggested that as epigenome writer, MGMT plays amore important role in papillary thyroid carcinogenesis than DNMT1.

کلیدواژه ها:

DNA methyltransferase ، Goiter papillary thyroid cancer