Factors Associated with Expression of Sodium/iodide Symporter (NIS) mRNA in Breast Cancer

Purpose: Cells of mammary gland as well as breast cancer uptake iodide through sodium/iodide symporter (NIS). The pathophysiologic importance of NIS is not evaluated well. The purpose of this study is to find relationships between the expression of NIS and other findings of breast cancer including ER, PR, C-erbB2, topoisomerase IIa, p53, and histologic grade of breast cancer. Methods: Fresh frozen specimens from 21 female breast cancer patients (mean age 50±13 years) with breast cancer were examined by RT-PCR for NIS mRNA. Immunohistochemical staining for ER, PR, C-erb B2, topoisomerase IIa and p53. Staging and degree of differentiation of cancer cells were also performed to evaluate the biological behavior of breast cancer. Results: NIS mRNA was expressed in 90% of the evaluated breast cancer tissues. The mean semiquantitative value of NIS mRNA in PR positive group was 2.02±0.35, which was higher than that of PR negative group (1.11±0.18; P=0.001). ER positive group showed higher value of NIS mRNA (2.02±0.35) than ER negative group (1.19±0.63; P=0.002). In addition, NIS mRNA values was significantly different according to differentiation of cancer cells (well differentiated type, 2.20±0.37 vs. less differentiated type, 1.39±0.63, P=0.01). However, there was no significant association between NIS mRNA levels and the other biologic characteriscs such as C-erb B2, topoisomerase IIa, and p53. Conclusion: The results showed that the expression of NIS in breast cancer may be associated with the presence of PR and ER as well as the degree of differentiation of breast cancer cells. (Journal of Korean Breast Cancer Society 2003;6:81-86)