Immunohistochemical Expression of the Human Sodium/Iodide Symporter Distinguishes Malignant From Benign Gastric Lesions

AIM: Sodium/iodide symporter (NIS) is a transmembrane protein that mediates the transport of I(-). The aim was to evaluate the immunohistochemical expression of the human homolog of NIS (hNIS) in a wide spectrum of gastric lesions. MATERIALS AND METHODS: Seventy-seven samples were stained immunohistochemically with a monoclonal antibody for hNIS, including 14 with normal gastric mucosa, 14 with chronic atrophic gastritis with foveolar hyperplasia, 15 with chronic atrophic gastritis with intestinal metaplasia, 6 with chronic atrophic gastritis with atypical regenerative hyperplasia, 8 with chronic atrophic gastritis with dysplasia, 15 with invasive adenocarcinoma, 3 with well-differentiated neuroendocrine tumor, and 2 with gastrointestinal stromal tumors (GISTs). RESULTS: hNIS stained the basolateral cytoplasmic portion of foveolae in normal mucosa, in 13 cases of chronic atrophic gastritis with foveolar hyperplasia, and in only 1 case of regenerative atypical hyperplasia. hNIS was consistently absent in intestinal metaplasia, in dysplastic glands, and in the cells constituting invasive carcinoma, well-differentiated neuroendocrine tumors, and GIST. CONCLUSION: It seems that lack of hNIS can be useful in distinguishing foveolar hyperplasia from dysplastic glands.