The percentage of CD3+CD4+/CD3+CD8+ T cells was 43.5%/21.6% in healthy volunteers and 41.3%/22.1% in the patients, respectively; it showed that the percentage of CD3+CD8+ T cells was no significant difference between healthy control and gastric cancer (P > 0.05), but the percentage of CD3+CD4+ T cells was significantly decreased in patients. Here, CD4 is linked to gastric cancer.