— In the march of metastasis, a molecular trail of crumbs guides some cancer cells from the primary tumor to establish new colonies within the body. Blocking the cells’ ability to follow the trail might halt metastasis but could also meddle with an intricate cellular signaling system critical to immune response. Purdue University scientists are deciphering this signaling system to better understand how it could be used to address multiple diseases, including cancer. As chemokines encounter cells, they bind to a receptor that spans the cell membrane, which triggers a response inside the cell. During metastasis, some cancer cells produce excess ACKR3 receptors that allow them to more easily follow the trail of chemokines to distant organs for colonization.