
Etiology
Many agents have been identified and are often associated. Conceptually, there are 2 types of agents that promote cancer, responsible for cell mutations (mutagens) and those who are responsible for promoting the transfer. Some factors, like tobacco, are both mutagens and promoters.
Chemical
They are very numerous, and the leader in tobacco is responsible for most cancers of the lung.
Tobacco remains the leading cause of cancer, of course, lung cancer and airways but beyond digestive cancers, kidney, urinary …
Alcohol is involved, particularly in the development of gastrointestinal cancers, but beyond in cancers of the oral cavity, larynx and even the female breast.