Effective analgesia can reduce the incidence of metastasis in cancer models.[21] Regional block anesthesia can protect NK cell activity by reducing neuroendocrine response mediated by surgery, increase anti-tumor cytokines such as IL-2 and IL-10 and decrease regulatory T cells, TH2 cells, and C-reactive protein, thus protect patients’ immune function to produce anti-tumor effect.[22] Our results may be related to the anesthetics and anesthesia methods. This evidence concerns the gene IL2 and cancer.