SOX2 and medullary thyroid gland carcinoma: DLK1+ subpopulations from both cell lines displayed heightened expression levels of pluripotency markers, such as SOX2, OCT3/4, and NANOG (p < 0.05), underscoring the association between DLK1 and the preservation of the CSC phenotype in MTC cell lines (Table 2 and Figure 6).