FOXP3 and cancer: In particular, the intensity of the tumoral immune response influences the effectiveness of cancer therapy; levels of tumor-infiltrating lymphocytes (TILs), such as CD3+, CD4+, CD8+, and factor forkhead box P3 (FoxP3+) T cells were proved to be an expression of immune response that is associated with patient survival in a wide variety of tumor types [5–8].