Contrary to popular opinion the brain contains more astrocytes than neurons. While astrocytes were originally viewed as "brain filling material", it is now well established that glial cells are indispensible for development, regeneration, and normal function of the nervous system. In fact, experimentally ablating astrocytes during development will eventually cause neurons to die. Similarly, injured neurons fail to regenerate in the absence of astrocytes. Moreover, astrocytes not only control function of neurons in the normal brain, but seem to contribute to or even cause the onset of various neuropathological conditions. A main interest of our group is to unravel the function of the chemokine, CXCL12, and its receptors, CXCR4 and CXCR7, in astrocytes of the healthy and diseased CNS. Another related project deals with the role of the CXCL12 chemokine system in the progression of gliomas, as well as tumors from other organs. We hope that our work will help to establish new chemokine-based therapeutical approaches for patients suffering from brain diseases as well as from cancer.