GPR137B and neoplasm: In line with this hypothesis, strong expression of the S100A11 and GPR137B genes has been reported at the protein level in PDAC tissues, while SULF1 and POSTN are expressed at more variable patterns [67-69]; of note all four proteins have been also found to be secreted and present in both tumor tissues and the plasma [67, 68, 70] from PDAC patients.