Evaluation of gene RASSF2 expression and methylation in tumor tissue and marginal tumor of tyroid cancer patients

Abstract

Thyroid cancer is one of the most common cancers among both males and females. One of the most important known changes in the process of malignancy, especially thyroid cancer, is epigenetic changes in the level of DNA methylation, which is associated with changes in the expression of various genes involved in the process of carcinogenesis. The RAS protein family is one of the most well-known oncogenes. These GTPases play a key role in the development and progression of cancer. The RASSF protein family (Ras Association Domain Family Member) is one of the most important suppressors of the Ras GTPase family, which are included in the group of tumor suppressor genes due to their function. RASSF2 is one of the important members of this 10-member protein family. In vitro studies have previously proven the role of this gene in inhibiting cell growth and inducing apoptosis. In this study, the expression level of this gene and its methylation in patients with thyroid cancer and their relationship with the clinical variables of the patients were investigated. Methods: In this research, 50 tumor tissue samples and 50 tumor margin samples of thyroid cancer patients were collected from the same patients, then RNA was extracted from the tissues to evaluate gene expression, and then cDNA was synthesized from it to examine the changes in RASSF2 gene expression. It was used by Real Time PCR. In the second part of the investigation, DNAs were first extracted, and after bisulfite treatment, the methylation level of the investigated gene was performed using the semi-quantitative MS-HRM method. In this study, pvalue<0.05 is considered as a significant level in all statistical tests. Results: According to the results obtained from the present investigation, the level of RASSF2 gene methylation in tumor samples has increased significantly compared to healthy samples, on the other hand, the expression level of the target gene in tumor samples has significantly decreased compared to healthy samples. Also, changes in the expression and methylation of this gene are related to some pathological features of patients such as metastasis. Also, the results of the ROC curve for the both expression and methylathion of the target gene showed that they have a biomarker value in differentiating tumor samples from healthy samples.