SOX2 and metastatic neoplasm: There were significant differences between primary and metastatic tumor cells throughout the sections, with 12 of 25 (48%) and 3 of 6, STAT3 was not expressed in either cell; whereas 12% and 16% of primary and metastatic tumor cells, respectively, showed positive expression of Nrf2, were positive for Nestin expression, and none of the cells tested positive for SOX2.