Regulatory T-cell density and cytotoxic T lymphocyte density are associated with complete response to neoadjuvant paclitaxel and carboplatin chemoradiotherapy in gastric cancer.

Regulatory T-cell density and cytotoxic T lymphocyte density are crucial in regulating antitumor immune responses. Tumor infiltration has marked therapeutic effects in gastric carcinoma, and there is evidence that chemoradiotherapy (CRT) exhibits an immune-mediated component. In the present study, the density of CD4 and CD8 cells were evaluated in post-CRT surgical samples from 68 patients with gastric cancer using immunohistochemistry. The associations between T-cell density, cytotoxic T lymphocyte density and clinical survival rate were also analyzed. Cytotoxic T lymphocyte density was associated with gastric carcinoma regression grade and regulatory T-cell density was also associated with gastric carcinoma regression grade. Of the patients who had a pathologic complete response, 84 and 76% were found to have a high CD3 and CD4 cell density, which was significantly different to patients who had a low CD3 and CD4 cell density. High cytotoxic T lymphocyte density was also associated with improved survival rates of patients with gastric cancer. In conclusion, these outcomes indicated that regulatory T-cell density and cytotoxic T lymphocyte density in the tumor microenvironment were associated with the response to neoadjuvant CRT and may represent a therapeutic target for gastric cancer.