We considered the possibility that the inflammatory stimulant NO is involved in the expression of CXCR4 in papillary thyroid carcinoma (PTC) because NO has been shown to up-regulate the expression of prometastatic and proangiogenic genes including VEGF [2], VEGF-C [3], and VEGF-D [4]. Here, CXCR4 is linked to differentiated thyroid carcinoma.