The upregulation of cell surface markers such as CD44, CD133, and ALDH1A1 has been linked to a poorer prognosis and increased resistance to chemotherapy and radiotherapy in both differentiated (DTC) and undifferentiated thyroid carcinomas (UTC) [21,64,65]. This evidence concerns the gene PROM1 and thyroid gland undifferentiated (anaplastic) carcinoma.