Just like immune cells can migrate through the membrane into the tumor, cancer cells can detach from the tumor, pass the membrane and migrate into the blood vessel mimic. By (directly or indirectly) coupling the cancer chip model to another model containing a potential metastatic organ site, such as a liver mimic, it is possible to study the process of metastasis. By introducing fluorescent reporter genes into the cells’ genome, the cells can be tracked and their behavior (for example the signaling pathway that is active) can be monitored by time-lapse fluorescence microscopy in real time. For experimental research all kinds of more complex configurations are conceivable, such as a series of identical chip modules, with or without a lymph node, or multiple potential metastatic sites, such as liver, lung, bone marrow and brain. However, metastatic organ sites on chip can also be used as independent modules.