PTGER4 and bladder transitional cell carcinoma: In the multifactorial Cox regression analysis, we found that genes SIGMAR1 (HR = 1.52, P < 0.001), OR2B6 (HR = 0.79, P = 0.017) and PTGER4 (HR = 0.86, P = 0.023) were independent risk factors for the prognosis of BLCA patients, OR2B6 and PTGER4 were protective factors for BLCA patients, while the opposite was true for SIGMAR1 (Figure 1c).