The cause of kidney cancer is not known, but some data show that its development is related to viruses, smoking, hormones, radiation, antipyretic and analgesic drugs, coffee, thorium, etc.; some other occupations such as oil, asbestos, leather and other industrial workers have high prevalence. Obesity and hypertension: A prospective study published in the November 2, 2000 issue of the New England Journal of Medicine showed that high body mass index (BMI) and hypertension are two independent factors associated with an increased risk of kidney cancer in men. Smoking: A large number of prospective observations have found that smoking is positively associated with kidney cancer development. The relative risk factor (RR) for kidney cancer in smokers = 2, and the risk of kidney cancer increases in those who have smoked for more than 30 years and smoked cigarettes without a filter. 3.Radiation: There are statistics that 26 out of 124 cases of tumors caused by the use of a weak alpha particle radiation source were confined to the kidney, but there are no reports of radiation exposure associated with kidney cancer in radiation workers and atomic bomb victims. 4.Occupation: Pathological specimens of kidney cancer have been reported, and an increased risk of kidney cancer incidence and death has been reported in workers exposed to metal store, newspaper printing workers, coke workers, dry cleaning industry and petrochemical product workers. 5. Food and drugs: Investigation found that high intake of dairy products, animal protein and fat and low intake of fruits and vegetables are risk factors for kidney cancer. Coffee may increase the risk of kidney cancer independent of the amount of coffee. In animal experiments, kidney cancer has been proven to be caused by female hormones (estrogen), but there is no direct evidence in humans. Abuse of antipyretic and analgesic drugs, especially those containing finasteride, may increase the risk of kidney cancer. Diuretics may also be a factor that promotes the development of kidney cancer. Animal experiments have led to the conclusion that red vine herb, also known as “Chiken”, may induce kidney cancer, and the Korea Food and Drug Safety Agency has asked domestic companies to stop producing red vine herb food additives. 6.Heredity: There are some intra-familial kidney cancer, which is found during chromosome examination. There is a defect on the third chromosome pair in people with high incidence of kidney cancer. Most familial kidney cancers have an early age of onset and tend to be multifocal and bilateral. As many as 28%-45% of patients with a rare hereditary disease, hereditary zebular pemphigoid (VHP) disease, develop kidney cancer. 7. Other diseases: In patients on long-term maintenance hemodialysis, there is an increase in the number of cases of cystic changes (acquired cystic disease) in the atrophied kidneys and then renal cancer is found. Therefore, those on dialysis for more than 3 years should have their kidneys examined annually by ultrasound. It has been reported that diabetic patients are more likely to develop kidney cancer. Fourteen percent of kidney cancer patients have diabetes mellitus, which is five times higher than that of the normal population.