Oral and maxillofacial cancer is the result of the interaction between multiple etiologic factors and multiple pathogenic conditions, although the specific pathogenesis is still unclear. At present, it is agreed that the occurrence of oral and maxillofacial cancer is related to the following pathogenic factors. (1) Physical factors: such as heat, injury, ultraviolet rays, X-rays and other radioactive substances, as well as long-term chronic stimulation, etc. become cancer-causing factors. For example, tongue and buccal mucous membrane cancer can occur in the corresponding parts which are stimulated by stumps, sharp tooth tips and bad restorations for a long time and often. (2) Chemical factors: Oral cancer is related to smoking and drinking. Tobacco and alcohol are carcinogenic sources, and they have synergistic carcinogenic effects. Long-term chewing of betel nut and other mixtures can cause the increase of basal cell division activity in the epithelial epithelium of oral mucosa, which induces the occurrence of oral cancer. (3) Biological factors: some viruses can cause the occurrence of malignant tumors. Current research has confirmed that human papilloma virus (HPV), especially HPV16, is the virus that induces squamous carcinoma of oral mucosa. (4) Nutritional factors: malnutrition or over-nutrition, including changes in recipes, certain vitamins and trace elements, have a certain relationship with the occurrence of cancer. Vitamins related to oral cancer are mainly vitamin A and vitamin B, and lack of E. In terms of trace elements, it is found that the content and ratio of selenium (Se), germanium (Ge), copper (Cu), zinc (Zn), etc., as well as carotenoids are related to the occurrence and development of carcinoma to a certain extent. (1) Neuropsychiatric factors: Experiments have proved that the level of hormone (corticosterone) in the blood of the body increases obviously when the body is nervous, the vitality of white blood cells in the circulating blood decreases, and the weight of immune organs in the body (thymus gland, spleen, lymph nodes, etc.) also decreases. In the clinic, we can also see that some tumor patients have a history of severe mental trauma before the onset of the disease, or still maintain abnormal mental state after the onset of the disease. The above facts show that excessive mental tension and disruption of psychological balance, resulting in dysfunction of human body, may be favorable factors for tumor development. (2) Endocrine factors: endocrine dysfunction can cause the occurrence of certain tumors, such as after suffering from breast cancer and cervical cancer, the chances of oral cavity and oropharyngeal cancer are greatly increased; some researches have reported that the risk of reoccurrence of breast cancer in female patients with salivary gland carcinoma is 8 times of that of normal people, which indicates that endocrine dysfunction also has a certain relationship with the occurrence and development of tumors. (3) Immunity status of the body: The immunity status of the body (especially cellular immunity) plays an important role in the development of malignant tumors. The immune function of patients with oral and maxillofacial malignant tumors decreases in both early and late-stage patients, and it is especially significant in late-stage cases. (4) Genetic factors: Cancer patients may have family history. The hereditary law of cancer is special, and the hereditary law of most cancers is expressed in the way of “susceptibility”, that is, what is inherited by the new generation is not the cancer itself, but a kind of individual quality that is prone to cancer, and it also needs certain environmental factors as the condition of its development. (5) Gene mutation: There are oncogenes and anticancer genes in human chromosomes. At present, it is confirmed that in oral and maxillofacial cancer, there are oncogenes such as C-Ha-ras, C-Ki-ras, C-myc and C-erbB, etc., and corresponding to oncogenes is the existence of anti-oncogenes (or oncogenes), such as p53, nm23 and Rb, etc. Under normal conditions, oncogenes and anti-oncogenes are not related to each other, but they can be found in human chromosomes. Under normal circumstances, oncogenes and anti-oncogenes are a pair of interdependent and mutually constraining factors, and the human body will not develop tumors. Only when the oncogenes are activated or the anticancer genes are inhibited (inactivated) under the action of various external factors will tumors appear in the human body. In addition, internal and external factors such as age, region, ethnicity, environment, customs and living habits are also closely related to the occurrence of tumors.