Expression of sodium-iodide symporter and TSH receptor in subclinical metastatic lymph nodes of papillary thyroid microcarcinoma.

Background The clinical significance of the subclinical lymph node (LN) metastasis in clinically node-negative (cN0) papillary thyroid microcarcinoma (PTMC) has been debated. We investigated the expression of sodium–iodide symporter (NIS) and thyroid-stimulating hormone receptor (TSHR) in the subclinical metastatic LNs of PTMC, which are crucial prerequisites for the response to radioactive iodine treatment.