The prognostic value of FOXP3+ T regulatory cells in colorectal cancer.

PURPOSE The evaluation of CD3(+) T-cell density is believed to have a higher prognostic value than the conventionally used TMN stage in colorectal cancer (CRC), but the role of regulatory T lymphocytes (Treg) is still debated. Our study determined the prognostic value of forkhead box P3 nuclear transcription factor (FOXP3) positive Treg and CD3(+) T-cells in the invasive margin of CRC compared with other known prognostic factors. METHODS The prognostic factors analysed in 42 patients with CRC stage II (N=13) and III (N=29), were age, tumor location, TNM stage, histological grade, vascular, lymphatic and perineural invasion. CD3(+) T-cells and FOXP3(+) Treg density was evaluated by immunohistochemistry. RESULTS The median CD3(+) T-cells and FOXP3(+) Treg density was 438.93/mm(2) and 162.25/mm(2), respectively. Patients with high FOXP3(+) Treg density showed improved 5-year survival rate of 89.41%, compared with 64.6% of those with low density (p=0.024). CONCLUSIONS Increased CD3(+) T-cells and FOXP3(+) Treg density is associated with improved survival, but only the latter proved to be an independent prognostic factor. FOXP3(+) Treg infiltrate may play an important prognostic role, which, in combination with other predictive factors, could lead to the development of specific treatment regimens.