Leukocytes can eliminate some of the tumor cells, the role of macrophages, B cells, T cells and NK cells, but once the tumor progresses and can not be completely killed. Tumor cells are normal cells with abnormal mutations, loss of gene regulation, which further leads to the generation of cellular heterogeneity, cell proliferation. Tumor cells that have just appeared can be extinguished by certain white blood cells in the body, so the human body itself has a certain mechanism to control the generation of malignant tumors; however, a large number of tumor cells proliferation as well as the fugitive nature of the tumor can not be completely eliminated. Once an obvious malignant tumor appears, it is necessary to consult a doctor for observation in time and carry out standardized treatment under the guidance of clinicians to avoid delaying the condition and affecting the prognosis.