Prognostic potential of tumoral FOXP3 expression in relation with tumor-infiltrating regulatory T cells in human gastric cancers.

Abstract

e15036 Background: Expression of the transcription factor FOXP3 is crucial for the regulatory T cells (Tregs) that engage in the maintenance of immunological self-tolerance and immune homeostasis. Recently, expression of FOXP3 in cancer cells and its association with prognosis have been shown in clinical studies. For gastric cancer, however, prognostic significance of the tumoral FOXP3 expression and its relationship with Tregs remains unknown. We observed the tumoral FOXP3 and Tregs from the 118 gastric cancer patients who underwent surgery to explore its relationships with the prognosis. Methods: Tissue samples from 118 cases of gastric cancer were used for the present study. We investigated the tumoral expression of FOXP3 and Tregs count in human gastric cancer tissue by the use of immunohistochemical analysis using a tissue microarray to explore the relation with clinicopathological variables by retrospective manner. Results: FOXP3-positive cancer cells were observed in 62 of 118 (52.5%) patients. Positive Tregs (Tregs≥10/HPF) were observed in 66 of 118 (55.9%) patients. There was significant positive relationship between positive Tregs count and the tumoral FOXP3 expression (P=0.006).Positive tumoral FOXP3 expression was significantly related with the better disease free survival but not with the overall survival. But increased Tregs count was significantly related with the better overall survival (P<0.01, P<0.01, respectively). When we divide the patients into four groups by the FOXP3 expression and the Tregs count, FOXP3/Tregs(+/+) group showed the best overall survival followed by FOXP3/Tregs(-/+) group, FOXP3/Tregs(+/-,) and FOXP3/Tregs(-/-), respectively. And the survival difference between the FOXP3/Tregs(+/+)-FOXP3/Tregs(-/+) group and the FOXP3/Tregs(+/-)-FOXP3/Tregs(-/-)group became more prominent by the Tregs count. Conclusions: These results suggest that positive tumoral FOXP3 expression in relation with the high Treg count is a new prognostic marker in gastric cancer. The combination of tumoral FOXP3 and Tregs enhanced its statistical power more than separated as a prognostic marker.