How do polycyclic aromatic hydrocarbons cause cancer?

1 Answer
Oct 26, 2016

Usually, their metabolic products cause mutations of DNA.


A polycyclic aromatic hydrocarbon (PAH) is an organic compound that is composed of several aromatic rings.

A common example is benzo[a]pyrene (BaP).

Many PAHs have much more potent metabolic products.

For example, BaP is metabolized to benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE).

An #"NH"_2"# group in the guanine and adenine units of DNA attacks the highly strained epoxide unit in BPDE binds.

The BPDE becomes covalently bonded to the DNA.

BPDE DNA adduct

The adduct causes a disruption in the structure of DNA.

(From Burning Issues)

If the body's DNA repair enzymes cannot remove the adduct, there will be an accumulation of changes during DNA replication.

These accumulated changes can lead to mutations, tumors, and cancers.