Radioiodide uptake and sodium iodide symporter expression in breast carcinoma

Breast cancer is a common malignancy in women all over the world and novel therapeutic approaches are required for the treatment of patients who become refractory to conventional therapies. Thyroid cancer is being treated successfully with radioiodine since many years. The iodide is transported inside the thyroid epithelial cell via sodium iodide symporter (NIS) which is a trans-membrane protein. The present study was aimed to explore the uptake of radioiodide (RAI) and the expression of NIS in breast tissues of invasive ductal carcinoma patients. Breast tissues from tumor region (Tu-Br) as well as corresponding normal region (N-Br) were collected from patients of invasive ductal carcinoma. In vitro RAI uptake, its efflux and NIS expression were studied. The uptake of RAI (1.98+/-1.75 x 10(5) cpm/g) in Tu-Br was significantly higher as compared to that observed in N-Br (0.31+/-0.27 x 10(5) cpm/g) and fast efflux was observed in the tissue samples. NIS gene expression was positive in 41.66% (10/24) samples of Tu-Br. None of the N-Br samples expressed NIS gene. In 14 samples of Tu-Br, RAI uptake as well as NIS expression was studied. In 50% of these Tu-Br samples RAI uptake as well as of NIS gene expression was positive. The results indicate that RAI uptake is significantly higher in breast tumor tissues as compared to their normal counterpart and in future radioiodine may be an important agent for treatment of breast cancer.