Furthermore, ROC curve analysis revealed the AUC values for lymphocytes, CD3+ T cells, CD8+ T cells, CD4+ T cells, and CD19+ B cells in GC patients to be 0.829 (0.743−0.915), 0.808 (0.722−0.894), 0.783 (0.689−0.876), 0.776 (0.681−0.871), and 0.836 (0.748−0.923), respectively. The gene discussed is CD19; the disease is gastric cancer.