Sundaraiya et al [13] suggested that changes in the expression of sodium iodide symporter, an integral plasma membrane glycoprotein that mediates the thyroidal uptake of 99mTc-pertechnetate, could explain the differences between the findings of 99mTc-pertechnetate scintigraphy for the primary thyroid lesion and the metastatic lesions. The gene discussed is SLC5A5; the disease is thyroid gland disorder.