The results indicated that PSME3 and PSME4 had high diagnostic performance for distinguishing patients with GC from healthy individuals (the AUC value for PSME3 and PSME4 was 0.808 and 0.821, respectively), while PSME1 and PSME2 had moderate performance (the AUC value for PSME1 and PSME2 was 0.557 and 0.452, respectively; Supplementary Figure 3). Here, PSME4 is linked to gastric cancer.