Introduction: Its well-known that outside of tumor cell is an acidic microenvironment, tumor cell survival and metastasis are closely related to the mechanism for a variety of complicated regulating process at the acidic microenvironment.Although several studies have shown that TDAG8 (T-cell death-associated gene 8 encoded receptor, G protein-coupled receptor 65) might involve in tumor cell survival in acidic condition, but its detailed molecular mechanism is still unclear.So, the study was designed to demonstrate a new mechanism of proton sensing receptor TDAG8 maintains tumor cell survival and metastasis under acidic condition resulting from MCTs (Monocarboxylate transporters) expression mediated by TDAG8 and its signaling mechanism.