TM4SF18 and gastric cancer: Thereafter, to evaluate the diagnostic efficacy of TM4SF18 and its ability to determine the prognosis of GC, we evaluated the survival of GC patients in the TCGA database and collected samples in the TM4SF18 high‐ and low‐expression groups using the Kaplan–Meier curve, and the results showed that the survival of GC patients in the high‐expression group was poorer than in the TM4SF18 low‐expression group (Fig. 1H,I).