We compared the mRNA levels of the relatively specific receptors and surface markers in PBMC from patients with those from healthy controls, and the results showed that the expression of T1/ST2, IL-17RB, and CRTH2 was significantly increased in gastric cancer, while the levels of ICOS and CD45 mRNA were significantly decreased (Figure 2). The gene discussed is PTGDR2; the disease is gastric cancer.