SFRP4 and cancer: In both the extragastric recurrence group (−2.8 ± 1.3 vs. −6.6 ± 1.8, p < 0.001) and the control group (−4.3 ± 1.6 vs. −7.1 ± 1.5, p < 0.001), SFRP4 expression was significantly higher in the submucosal cancer tissue than that in the mucosal layer.