RASSF1 and thyroid cancer: Among the eight TSGs identified in our study, hyper methylation in the promoter region of seven thyroid cancer-associated genes (RASSF1, TSHR, PTEN, SLC5A, DAPK, P16, and CDH1) was associated with an increased risk of thyroid cancer with an OR of 2 or more, and one gene (RARβ2) was associated with increased risk of thyroid cancer with an OR of 2 or less.