However, the methylation status in a CpG island at the proximal promoter region of the PTTG1/securin gene was not evaluated in this study since no methylation was observed in either healthy tissues or differentiated thyroid carcinoma samples, or in prostate cancer cell lines regardless of the expression status of PTTG1/securin gene [41]. This evidence concerns the gene PTTG1 and thyroid gland carcinoma.