Asked in Lung Cancer
Lung Cancer

What part of a cigarette causes lung cancer?


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The Nicotine and the Tar

Nicotine does not directly cause cancer, but is instead the addictive compound recognized by nicotinic receptors. While nicotine is not mutagenic, the addiction created by the bodies craving for results in the uptake of carninogens. Tar is a generalized term for any substance that coats. In this case Tar is a residue formed by the burning of tobacco. Tar coats the alveoli of lungs, thereby decreasing air exchange and contains several mutagens.

Benzo(a)pyrene [B(a)P] diolepoxide (BPDE) is the substance found in cigarette smoke which causes mutations in the P53 gene. P53 is one of the "gatekeepers" of the genome and if mutations occur that affect its function, the cell can lose proofreading ability during replication thereby allowing cancerous cells to form. BPDE is formed by the burning of tobacco (heat activated), and is also found when wood is burned, or steaks are overcooked.