Conclusions
We have demonstrated that the increased prevalence of tumor-infiltrating Tregs closely related to their lower sensitivity to H(2)O(2)-induced apoptosis.
Results
The increased tumor-infiltrating Tregs coexisted with elevated H(2)O(2) production according to disease progression. The grade of apoptosis in Tregs was less pronounced than that in conventional T cells, and there was a positive correlation between H(2)O(2) production and the grade of apoptosis in conventional T cells, while there was no correlation between H(2)O(2) production and the grade of apoptosis in Tregs. Moreover, Tregs were less sensitive to H(2)O(2)-induced apoptosis compared with conventional T cells in vitro. Conclusions: We have demonstrated that the increased prevalence of tumor-infiltrating Tregs closely related to their lower sensitivity to H(2)O(2)-induced apoptosis.