Immunohistochemical Expression of the Sodium/Iodide Symporter in Patients with Primary Lung Cancer

ABSTRACT

BACKGROUND: The sodium/iodide symporter (NIS) is a membrane glycoprotein that facilitates the uptake of iodine by thyroid follicular cells. Although the use of radioiodide is essential for the diagnosis and treatment of thyroid diseases, few studies have been conducted to investigate the use of NIS-mediated radioiodide accumulation in lung cancer. We evaluated the expression of NIS by immunohistochemistry in order to examine the diagnostic or therapeutic feasibility of using radioiodide in the treatment of primary lung cancer. METHODS: Immunohistochemistry for NIS was performed in 139 lung cancers. The expression pattern of NIS was compared with the clinicopathological characteristics of the tumors. RESULTS: NIS immunoreactivity was detected in 75 (54.0%) of the 139 cases. Twenty-three (37.7%) of the 61 squamous cell carcinomas, 49 (76.6%) of the 64 adenocarcinomas, 2 (40.0%) of the 5 small cell carcinomas, and 3 (33.3%) of the 9 other carcinomas showed positive NIS immunoreactivity. The expression of NIS was significantly associated with the histologic type (p<0.001), but it did not correlate with tumor size, lymphovascular invasion or lymph node metastasis. CONCLUSIONS: The presence of NIS was detected in lung cancer tissue using immunohistochemistry. Lung cancer potentially could be targeted with radioiodide for both diagnosis and treatment, especially in cases of adenocarcinoma.