What are the causes of benign tumors in the cardia?

1. Indirectly acting chemical carcinogens: polycyclic aromatic hydrocarbons, aromatic amines and azo dyes, nitrosamines, and mycotoxins.

2. Direct effects of chemical carcinogens: These carcinogens can cause cancer without activation in the body, such as alkylating agents and acylating agents.

1. Nitrosamines are carcinogens that can cause various cancers in animals. Spoiled vegetables and food have high levels of nitrosamines, which can cause tumors in the digestive system, kidneys, and other organs.

2. Polycyclic aromatic hydrocarbons, represented by benzo[a]pyrene, can cause skin cancer when applied to animal skin and sarcomas when injected subcutaneously. They are found in vehicle exhaust, soot, cigarettes, and smoked foods.

3. Alkylating agents, such as mustard gas and cyclophosphamide, can cause leukemia, lung cancer, breast cancer, etc.

4. Vinyl chloride is the most widely used plastic, polyvinyl chloride, which is polymerized from vinyl chloride monomers. It can induce tumors in the lungs, skin, and bones. Vinyl chloride can also cause angiosarcoma of the liver with a latency period generally exceeding 15 years.

5. Certain metals such as chromium, nickel, and arsenic can also cause cancer.