Catch me if you can! Novel immune escape mechanisms in melanoma metastases of the brai

The immune system is one of the key modulator directing tumor growth and progression, but also therapy responsiveness. Recent reports clearly idicate that drug activity in the brain is not only directed by the drug susceptibility to penetrate the blood-brain-barrier, but is most likely modulated by the cellular composition of the brain-specific metastatic niche which modulates establishment and outgrowth of brain metastases. The immune microenvironment in brain metastases is active with a high density of tumor-infiltrating lymphocytes in certain patients and, therefore, may serve as a potential treatment target. To study the reciprocal communication between tumor cells and the immunoactive infiltrate in the brain but also its impact on therapy efficacy, we were able to establish new preclinical models which allow for the first time to study homing specific mechanisms of brainseeking melanoma cells in the presence of an intact immune system. By using our novel models, we were able to identify unknown immune escape mechanism of melanoma cells penetrating the brain