The concept of personalized tumor therapy is based on the use of specific, custom-tailored medication to treat an individual’s cancer. Besides comprehensive knowledge about the tumor’s molecular properties, development of such treatment strategies benefits considerably from the use of cell models representing the actual target cells of the individualized therapy. Such cell models are needed to test novel therapeutics and to study the biology of specific tumor cell populations. Tumor cells that have already spread in the body – e.g. disseminated tumor cells (DTC), which are metastatic progenitor cells, and circulating tumor cells (CTC) in the patient’s blood – are important target cells for specific therapy approaches in patients with metastatic disease.
Due to the very low abundance of DTC and CTC and the resulting difficulty to detect and enrich them, it is nearly impossible at present to expand these cells and thereby establish representative models for preclinical drug testing. The use of cell models based on these rare cells, however, will enable a deeper understanding of metastasis formation and improved testing of novel therapeutics.