 Human mesenchymal stem cells, MSCs, have been shown to respond to homing signals in order to migrate to sites of injury in the body. These signals can be generated by the local environment, such as inflammation, or by the presence of certain cell types within the area. Increasing the number of MSCs at the site of injury through manipulation of the environment or genetic modification of the cells themselves could potentially increase their effectiveness in treating injuries. This article was authored by Sungkwon Kang, Illinois C-Option, Myung Sin K.O., and others.