[Lani]

I had heard of this research about 6 months ago--now the paper is out. I don't know when they might be trying using radioactive iodine (already FDA approved for thyroid cancer and widely used), but will try to find out if there are trials and if you have to have had a brain biopsy showing NaI symporter
present on the mets.

: J Neurooncol. 2009 Jul 19. [Epub ahead of print]

Breast cancer brain metastases express the sodium iodide symporter.

Renier C, Vogel H, Offor O, Yao C, Wapnir I.
Department of Surgery, Stanford University School of Medicine, 300 Pasteur Drive H 3625, Stanford, 94305-5655, CA, USA.
Breast cancer brain metastases are on the rise and their treatment is hampered by the limited entry and efficacy of anticancer drugs in this sanctuary. The sodium iodide symporter, NIS, actively transports iodide across the plasma membrane and is exploited clinically to deliver radioactive iodide into cells. As in thyroid cancers, NIS is expressed in many breast cancers including primary and metastatic tumors. In this study NIS expression was analyzed for the first time in 28 cases of breast cancer brain metastases using a polyclonal anti-NIS antibody directed against the terminal C-peptide of human NIS gene and immunohistochemical methods. Twenty-five tumors (84%) in this retrospective series were estrogen/progesterone receptor-negative and 15 (53.6%) were HER2+. Overall 21 (75%) cases and 80% of HER2 positive metastases were NIS positive. While the predominant pattern of NIS immunoreactivity is intracellular, plasma membrane immunopositivity was detected at least focally in 23.8% of NIS-positive samples. Altogether, these findings indicate that NIS expression is prevalent in breast cancer brain metastases and could have a therapeutic role via the delivery of radioactive iodide and selective ablation of tumor cells.
PMID: 19618116 [