PTGDR2 and colorectal cancer: As an important mediator in the process of inflammation, GPR44 contributes to canceration in various systems of the human body according to previous research in lung cancer [36], gastric cancer [37], leukemia [38,39], osteosarcoma, colorectal cancer [40,41], breast cancer [42], multiple myeloma [43], and hepatocellular carcinoma [44].