Localisation pattern of Foxp3+ regulatory T cells is associated with clinical behaviour in gastric cancer

Abstract

It has been reported that the population of regulatory T cells (T regs) is increased in tumour-infiltrating lymphocytes in cancer-bearing hosts. Recently, forkhead/winged helix transcription factor p3, Foxp3, is thought to be the most reliable marker of T regs. In the present study, we investigated the prevalence and localisation pattern of Foxp3⁺ cells in gastric cancer (n=80) by immunohistochemistry, in relation to the clinical outcome of gastric cancer patients. Immunohistochemical staining was performed with anti-Foxp3 mAb, and Foxp3⁺ cells were semiquantified. We divided all cases into two groups: Foxp3⁺-high (n=40) and Foxp3⁺-low (n=40) groups, by the median size of the population of Foxp3⁺ cells. Furthermore, in terms of the localisation pattern of accumulating Foxp3⁺ cells in tumours, we classified all cases into three groups: a peri-tumour group (n=30), a diffuse group (n=40), and a follicular group (n=10). As a result, although the populations of Foxp3⁺ cells in stage IV were significantly larger than those in stage I (P+ cells. However, survival in patients with a diffuse pattern of Foxp3⁺ cells was significantly poorer than in those with a peri-tumoral pattern. In conclusion, the localisation pattern, but not the population size, of Foxp3⁺ cells was significantly related to patient survival.