Relationship between the expression of sodium iodide symporter and the findings of 99mTc-MIBI scintimammography in the primary breast cancer

Human Na+/I- symporter (hNIS) is known to be expressed in many tissues other than thyroid gland. The breast cancer cells are one of them and the possibility of radioiodine therapy in treatment of the breast cancer may be suggested. We investigated the expression rate of hNIS and the relationship between the expression of hNIS and the finding of 99mTc-MIBI scintimammography in the breast cancer. Surgically proved 56 patients with breast cancer were the subjects of this study. The expression of hNIS were evaluated by immunohistochemistry and the results were compared to the findings of 99mTc-MIBI scintimammography. Overall expression rate of hNIS was 41.1% in 56 patients. According to the pathologic diagnosis, it was 42.9% in 49 patients with invasive ductal carcinoma and 28.6% in the 7 patients with ductal carcinoma in situ. The expression rate of hNIS in the 41 cases with a focal increased uptake at he breast lesion on 99mTc-MIBI scintimammogram was 31.7%. That in the 15 cases without any abnormal uptake on the scan was significantly higher(66.7%, p<0.05). The expression rate on hNIS in the patients with breast cancer was not so high. The rate was higher in the patients with no increased uptake at the breast lesion on 99mTc-MIBI scintimammography