Cancer, the last “natural enemy” of mankind in the physical and spiritual worlds. In the English dictionary, there is a very relevant and thought-provoking definition of cancer: 1) cancer, malignant tumor; 2) malady, social vice; a rapidly spreading bad or dangerous thing. The following are the interpretations based on this definition.1. Biological definition: Clinical symptomology is: a malignant disease that grows, spreads and metastasizes rapidly in the human body and finally kills people. 2. Sociological definition: A rapidly spreading bad or dangerous thing, the specific “clinical signs and symptoms” are “the 12 evils of human nature”, they are: power, money, greed, selfishness, jealousy, hatred, fraud, domination, indulgence, promiscuity, abuse, and killing. They are: power, money, greed, selfishness, jealousy, hatred, fraud, domination, indulgence, lewdness, wantonness, abuse, killing. The 12 evils cause the loss of human morality, moral corruption, the sale of flesh and soul, and ultimately lead to the weakening of nations, the collapse of societies, the change of dynasties, or even the destruction and disappearance of nations. The tragedy of cancer has been continuously played out in people and societies all over the world, and the thousand-year history of both ancient and modern countries can bear witness to this. This is cancer in a broad sense. No need to have high and deep knowledge and experience, and no matter if they know medicine or not, they all know clearly that they are consciously or unconsciously involved in the door of cancer, experiencing and experiencing the gloom of cancer and tasting its bitter fruit. 3. Philosophical definition: Cancer is a “divine beast” bred by nature, guarding the sanctuary of reason and morality. In front of the door. If you work honestly within the bottom line of reason and morality, you will be prosperous, flourishing, healthy and long-lived; if you want to play tricks and cleverness and cross the bottom line, you may be disillusioned, failed, sick and have cancer. Philosophy is relentless and points to the depths of the human soul and pain. Those who understand it will know it by heart; those who understand it will feel free.