Expression of the sodium/iodide symporter in human prostate adenocarcinoma

OBJECTIVE: To analyze expression of the sodium/iodide symporter (NIS) in tissue specimen from a large series of patients with prostate adenocarcinoma. Few data are available on the NIS expression in prostate tumor tissues. METHODS: NIS protein expression was examined by immunohistochemistry in 78 tumor tissue specimen and their non-neoplastic counterparts. Total ribonucleic acid was extracted for semiquantitative reverse transcription polymerase chain reaction analysis of NIS transcript. The relationship between NIS expression and Gleason score, prostate-specific antigen levels and stage was also investigated. RESULTS: NIS protein was expressed in 41 of 78 prostate cancer (52.4%) and was located predominantly intracellularly, whereas immunoreactivity was missing in nontumor hyperplastic prostatic tissue. Absence of expression was mainly because of reduced or lost gene transcription, as detected by reverse transcription polymerase chain reaction. A statistically significant relationship was detected between presence of NIS expression and some markers of aggressiveness including stage > or =pT2a (P = .007) and Gleason score > or =8 (P = .014). CONCLUSIONS: Our data demonstrate the presence of NIS transcript and protein in about half of prostate cancer tissues and its relationship with clinical markers of aggressiveness. Thus, it may potentially serve as a biomarker for defining individuals with biologically active prostate cancer.