Correlation between sodium-iodide symporter expression and circulating tumor cell positivity in differentiated thyroid carcinoma

Objective We investigated the correlation between the expression of the sodium-iodide symporter(NIS) and the detection of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC).Methods NIS expression in differentiated thyroid and the positive rate of CTCs in the peripheral blood were determined by immunohistochemistry S-P and flow cytometry from the records of 172 cases of differentiated thyroid carcinoma.Results Seventy-six cases(44.2%) expressed NIS in the differentiated thyroid and 63 cases(36.6%) were positive for CTCs in the peripheral blood. There was a significant difference between N0 and N1 in the expression of NIS(χ~2 = 6.015, P = 0.014) and the positive rate of CTCs(χ~2 = 14.035, P = 0.001). N0 and N1 also differed significantly in the expression of NIS(r =-0.383,-0.610, P = 0.002, < 0.001). The differences in the NIS expression, but not in the positive rate of CTCs, were significant among the different pathological subtypes(χ~2 = 7.897, P = 0.005; χ~2 = 1.455, P = 0.228, respectively). There was a significant negative correlation between the highly differentiated type and intermediate differentiation type both in the expression of NIS and positive rate of CTCs(r =-0.591,-0.443, P < 0.001, P = 0.002). Conclusion There was a significant negative correlation between the expression of tissue NIS and positive rate of CTCs in the peripheral blood in DTC. The malignancy level and lymph node metastasis in differentiated thyroid carcinoma were negatively correlated with NIS expression and positively correlated with the positive rate of CTC.