The present invention relates to a method for diagnosing and/or treating sodium-iodide symporter (NIS)-expressing primary carcinomas and metastases, preferably glandular carcinomas, in particular carcinomas of the thyroid, of the salivary gland, of the uterus and carcinomas of the breast, and to a pharmacological composition comprising substances which induce and/or increase the expression or function of the NIS symporter and, as a consequence, increase iodide uptake into the cells, and to corresponding uses. This can be used for an efficient tumor-specific radioiodide uptake in diagnosis and therapy of said carcinomas and metastases.
