F2RL1 and cancer: Previous studies have established a link between trypsin expression and activated signaling systems—such as PAR-2—with effect on cancer growth of pancreatic cancers.47–51 Very high expression of PAR-2 has been found in certain tumor cell lines derived from the lung, colon, and pancreas.52 Pancreatic cancer cell lines containing PAR-2 proliferate upon exposure to trypsin, whereas the cancer cell line not containing PAR-2 failed to proliferate upon trypsin exposure.23 This suggests that the presence of PAR-2 is needed for trypsin to induce proliferation in cancer cells.