Through the immunohistochemical study of the tumor tissues of 74 patients with PTC, it was found that the characteristics of EMT (positive expression of E-cadherin, negative expression of Vimentin) and down-regulation of CD8+ surface markers occurred at the same time, and the characteristic changes were more significant in patients with lymph node metastasis and lymphatic invasion [88]. This evidence concerns the gene CD8A and neoplasm.