The clinical significance of memory T cells and its subsets in gastric cancer

Background

Long life of memory T cell (Tm) determines its crucial role in the carcinogenesis and carcinogenic progression which usually take long time. The Tm compartment contains two populations, central memory T cells (Tcm) and effector memory T cells (Tem), based on their phenotypic markers, functional attributes, and migratory properties.

Methods

We investigated the subsets of the Tm in peripheral blood and tumor microenvironments in patients with gastric cancer by flow cytometry, and aimed to explore the correlation between the Tm and clinicopathologic features of gastric cancer.

Results

The percentages of CD4⁺/CD8⁺ Tm and CD4⁺/CD8⁺ Tcm in peripheral blood from gastric cancer patients were statistically lower, whereas the percentages of CD4⁺/CD8⁺ Tem were significantly higher than healthy controls. The proportion of CD4⁺/CD8⁺ Tcm increased after tumor resection, while the percentage of the CD4⁺/CD8⁺ Tem decreased significantly. Significant associations were detected between the peripheral CD4⁺/CD8⁺ Tm and clinical stage, as well as the CD8⁺ Tcm and clinical stage and nodal involvement. Tumor infiltrating CD8⁺ Tm expressed both central and effector memory phenotypes, whereas CD4⁺ Tm displayed predominantly an effector memory phenotype. Higher percentages of tumor infiltrating CD4⁺/CD8⁺ Tm were significantly associated with the early disease stage.

Conclusions

Tm and its subsets were good immune indicators for the disease stage of gastric cancer. The proportion of Tm subsets may reflect the immune suppressive and immune response to the tumor associated antigen.