Laboratory mice. A technician with a bald mice. Cages of laboratory mice undergoing experimentation. Experiments are distinguished by labels on each cage. Laboratory mice are the most commonly used animals for biological and medical experiments. Such research is either to test the safety of non medical substances (such as cosmetics or pesticides) or medical experiments to test for the effects of new drugs or oncology research. At INT several transgenic mice reproducing the characteristic of human cancers occuring in prostate, mammary gland, thyroid, colon and melanocytes have been created and collected. This large mice collection has had an impact on studies at INT allowing the discovery of new processes related to tumor biology, immunotherapy and chemotherapy, and, more importantly, enabling us to investigate the underlying mechanism. However, many animal experiments remain compulsory by law before new products can be released.