G protein-coupled receptors (GPRs) are highly related to oncogenesis and cancer metastasis. G protein-coupled receptor 137 (GPR137) was initially reported as a novel orphan GPR about 10 years ago. GPR137 is ubiquitously expressed in the central nervous system (CNS), mainly in the hippocampus . GPR137 is involved in the progression of human glioma, suggesting GPR137 as a potential oncogene of glioma cells . Recent study shows that GPR137 plays an important role in colon cancer cell proliferation .