Conversely, anaplastic thyroid carcinomas retain cytokeratin expression in approximately 70% of cases [73] with 54 − 70% of them also exhibiting strong PAX8 staining [73, 74], whereas reactivity for vascular markers is only focal and observed in a minor subset of tumors. Here, PAX8 is linked to thyroid gland undifferentiated (anaplastic) carcinoma.