Exposure to benzo[a]pyrene and breast cancer : a systematic review

Objective: Breast cancer is the most common invasive cancer in women in the world. Benzo[a]pyrene (B[a]P), a carcinogenic component of cigarette smoke and grilled meat, was related to expression of enzymes involved in several epithelial malignancies including breast cancer. Understanding the association of exposure to B[a]P and breast cancer risks may inform potential disease preventive measures. The objective of this systematic review was to assess from epidemiological studies the relationship between the exposure to and the risks and development of breast cancer in humans. Study design: A systematic search using keywords in PubMed (1990-2014), CNKI (1994-2014) and Google Scholar databases was carried out to identify eligible epidemiological studies on the association between the exposure to B[alP and breast cancer risks published during 1990-2014. Results: Nine studies met the inclusion criteria and included in this review. All nine included studies used case-control design, with B[a]P exposure mainly proxied by benzo(a)pyrene diolepoxide (BPDE) and dietary consumption of B[a]P-rich food. Of these, seven found a significant positive association between B[a]P exposure and breast cancer risks, after adjustment for age, family history of breast cancer, smoking, ethnicity, alcohol use and parity in most studies. Discussion: Discuss the potential reason for inconsistence, the possible biological pathways explaining the role of B[a]P in the development of breast cancer, limitations of the studies and the public health implication from this review. Conclusion: A positive association between B[a]P exposure and breast cancer risks was suggestive from the systematic review. However given the limited number of studies included, further prospective cohort studies in humans as well as molecular/animal studies are warranted to explore the impact of B[a]P on the development of breast cancer to inform evidence based preventive measures against breast cancer.published_or_final_versionPublic HealthMasterMaster of Public Healt