CIBERSORT algorithms were employed to measure the enrichment scores of immune-related cells in the two PCDI groups, which revealed higher levels of resting CD4+ memory T cells and lower levels of activated CD4+ memory T cells in the high-PCDI group than in the low-PCDI group, suggesting that the reduction in activated resting CD4+ memory T cells may contribute to a poor prognosis in high-PCDI GC patients (Supplementary Figure 6). This evidence concerns the gene CD4 and gastric cancer.