Bedeutung von Stammzellen in der Biologie und Therapie von Kopf-Hals-Karzinomen

Stem cells play a central role in re- and generation of tissues. Special importance has been attributed to them in cancer biology. 2 entities can be discriminated: cancer infiltrating stem cells and cancer initiating stem cells. Infiltrating stem cells will be attracted to the tumor in order to be remodelled for tumor expansion, e. g. endothelial cells or other cancerous tissue components, yet these cells are per se benign. Malignant cancer stem cells are capable to generate a new tumor, histologically identical with the cancer they originate from. Many steps in cancer stem cell biology are not understood to date. It is still believed that CSC are only a minor cell fraction in tumor but capable to differentiate in hierarchical manner into any other tissue type. These stem cells are undergoing many steps of differentiation and dedifferentiation in a steady state. The factors of the micromilieu contributing to this are largely not understood. Still these steps are regarded as the key to tumorinitiation, metastases and resistance to therapy. The biological functions and associated signaltransduction pathways, e. g. self renewal pathways will be the key to future therapeutical strategies.