The Xu laboratory investigates the mechanism of metastasis, the spread of cancer cells from their original loci to other parts of the body. It is the major cause of death in cancer patients, but exactly how it occurs is not clear. Metastasis involves multiple levels of interactions between migrating tumor cells and their microenvironment. Understanding these interactions will greatly enhance our knowledge on metastasis and lead to a better treatment of cancer. A major focus of the laboratory is to dissect these interactions by studying the functions of a new family of cell surface receptors, called adhesion G protein-coupled receptors (GPCRs), during tumor spread. One of the adhesion GPCRs, GPR56, was found to play inhibitory roles in metastatic growth of melanoma cells. We explore its regulatory mechanisms using xenograft models, knockout mice, transgenic tumor models, as well as various biochemical and bioinformatics tools.