[Clinical significance of identification and characterization of circulating tumor cells]

Cancer is characterized by the fact that years after the primary curative treatment metastases might develop. Due to the good vascularisation of primary tumors single cells might drip into the blood vessels and get a chance to reach other organs including the bone marrow. This means that there is always the possibility that metastases develop. IDENTIFICATION OF TUMOR CELLS: Disseminating tumor cells have their characteristic patterns of somatic mutations. This means that they can be identified and characterized by molecular-genetic techniques. They can be studied with regard to their origin and their ability to metastasize. Furthermore, their sensitivity or resistance with regard to chemotherapy can be identified.

In order to study circulating tumor cells these have to be extracted from peripheral blood. The first step is to isolate mononucleated cells from the blood. The second step is to separate the normal blood cells from other mononucleated cells. The third step is to extract and analyse DNA and RNA from these cells focussing on specific mutations of oncogenes and tumor suppressor genes.

The identification of circulating tumor cells helps to identify suspect clinical results, reveals minimal residual disease and might support individual therapeutic strategies.