A new study has reported that exposure to polycyclic aromatic hydrocarbons (PAHs) increases breast cancer risk in part through p53 mutations. PAHs have previously been reported to be associated with breast cancer. However, the mechanism of carcinogenicity of PAHs on human breast tissue remains unclear. Certain carcinogens have been found to be associated with specific mutation patterns in the p53 tumor suppressor gene. The authors therefore hypothesized that the impact of PAH-related exposures on breast cancer risk would differ according to tumor p53 mutation status, effect, type, and number. In the study, 151 p53 mutations among 859 breast tumors were identified and confirmed. Exposure to PAHs in study participants was assessed based on smoking status in 859 breast cancer cases and 1,556 controls, grilled/smoked meat intake in 822 cases and 1,475 controls, and cellular markers of PAH-related DNA damage in 487 cases and 941 controls.

Unexpectedly, participants with p53 mutations were found to be less likely to be exposed to PAHs than participants without p53 mutations. For example, active and passive smoking was significantly associated with p53 mutation-negative cancer but not with p53 mutation-positive cancer. However, several types of mutations and number of mutations were consistently elevated among exposed subjects. The authors conclude that PAHs may be associated with specific breast tumor p53 mutation subgroups rather than with overall p53 mutations. PAHs exposure may also be related to breast cancer through mechanisms other than p53 mutation.

Sources of PAH exposure

Polycyclic aromatic hydrocarbons such as acenaphthene, anthracene, benzo(a)pyrene, benzo(e)pyrene, benz(ghi)perylene, chrysene, coronene, cyclopenta(def)phenanthrene, phenanthrene, and pyrene are known or suspected to increase the risk of various types of cancer. The PAH benzo[a]pyrene is routinely used in animal studies to promote breast cancer development. PAHs are found in significant amounts in the following:
Well-done, broiled, and deep-fried meat
Cooking oil fumes
Tobacco smoke
Yerba maté
The following foods or their extracts have been shown to reduce the harmful influence of PAHs on cancer development in animal studies:
Basil
Black pepper
Grapes, red
Honey
Mangoes
Pepppermint
Mustard
Papayas
Passion fruit
Spinach
Turmeric