T-regulatory lymphocytes in peripheral blood of gastric and colorectal cancer patients.

AIM

To assess the absolute number of T-regulatory cells (Tregs; CD4+CD25+Foxp3+) in the peripheral blood of gastric and colorectal cancer patients.

METHODS

We enrolled 70 cancer patients (33 gastric cancer, 37 colorectal cancer) and 17 healthy volunteers. The CD3+CD4+ lymphocytes and CD4+CD25+Foxp3+ Tregs in the peripheral blood were analyzed with flow cytometry. The absolute numbers of Tregs were calculated based on the CD4+CD25+Foxp3+ cells percentage of CD3+CD4+ cells and the absolute numbers of CD3+CD4+ cells per microliter.

RESULTS

The mean number of CD4+CD25+Foxp3+ cells per microliter in colorectal cancer patients was 15.7 (SD: 21.8), for gastric cancer patients 12.2 (SD: 14.3), and for controls 17.5 (SD: 11.4). The absolute number of Tregs was significantly lower in gastric cancer patients than in controls (P = 0.026). There was no statistically significant difference for gastric vs colorectal cancer or colorectal cancer vs controls. The absolute number of Tregs was also significantly depressed in N+ vs N⁻ cancer patients [22.0 (27.7) vs 10.1 (9.0), P = 0.013], and in the subgroup of gastric cancer patients [30.3 (27.6) vs 9.6 (8.0), P = 0.003]. No statistical difference was observed in the proportion of Tregs in the CD4+ population between the groups.

CONCLUSION

The absolute number of Tregs in peripheral blood of gastric cancer but not colorectal cancer patients was significantly decreased in comparison with that in healthy controls.