Department of Molecular Pharmacology (O.D., N.C.), Albert Einstein College of Medicine, Bronx, New York 10461; Department of Pathology (Z.Ba., V.L.), University of Pennsylvania, Philadelphia, Pennsylvania 19104; and Department of Pathology (Z.Bá.), Faculty of Health Sciences of the Semmelweis University, Budapest, Hungary
Address correspondence to: Nancy Carrasco, M.D., Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, F-209, Bronx, New York 10461.
Abstract
Here we report the analysis of the Na+/I-
symporter (NIS) protein expression in 57 thyroid cancer samples by
immunohistochemistry with high-affinity anti-NIS Abs. As many as 70%
of these samples exhibited increased NIS expression with respect to the
normal surrounding thyroid tissue. Most significantly, NIS was located
in these samples either in both the plasma membrane and intracellular
compartments simultaneously, or exclusively in intracellular
compartments. This suggests that NIS is clearly expressed or even
overexpressed in most thyroid cancer cells, but malignant
transformation in some of these cells interferes either with the proper
targeting of NIS to the plasma membrane, or with the mechanisms that
retain NIS in the plasma membrane after it has been targeted. The
results further indicate that, in addition to indicating NIS expression
in cases where it is absent (30%), improvements in 131I
radioablation therapy might result from promoting targeting of NIS to
the plasma membrane in the majority (
70%) of thyroid cancers.