title: Effects of ambient particulate matter on human breast cancer: is xenogenesis responsible?
abstract: BACKGROUND
  Recently, evidence from several studies has revealed that air pollution is associated with the increased morbidity and mortality of breast cancer patients. However, to date, the underlying mechanism remains largely unclear. Considering the high prevalence of air pollution and breast cancer in China, it is necessary to understand how air pollution may affect breast cancer.
  
  
  METHODS
  We analyzed 1,832 female patients who had resided in the same cities for at least 10 years prior to their diagnosis. Variables including demographic data as well as clinical and tumor characteristics, including the patient's age at menarche, family history of breast cancer, tumor histopathological type, tumor size, lymph node metastasis, distant metastasis, histological grade, estrogen receptor (ER) status, progesterone receptor (PR) status and human epidermal growth factor receptor 2 (HER-2) status at the time of diagnosis were analyzed.
  
  
  RESULTS
  Compared to patients residing in low-pollution areas, patients living in high-pollution areas demonstrated a younger age at menarche (p<0.001), a greater family history of breast cancer (p = 0.034) and more invasive cancers (p = 0.028) with higher tumor grades (p = 0.028) and estrogen receptor (ER)-positive status (p = 0.022). Differences in tumor grade were only found in ER-positive cases.
  
  
  CONCLUSIONS
  Our findings and clinical data indicate that long-term air pollution exposure may contribute to the development of breast cancer by playing the role of a xenoestrogen, and also provides new insight into the association between air pollution and the morbidity and mortality of breast cancer patients. Furthermore, it is urgently necessary to study the association between air pollution and breast cancer to improve the living quality and health of females, and applicable public health strategies may need to be established or modified as soon as possible.
authors.affiliation: Department of Breast Surgery, Qilu Hospital of Shandong University, Shandong, China ; School of Medicine, Shandong University, Shandong, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Huo
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Wang
authors.forename: Liyu
authors.initials: L
authors.lastname: Jiang
authors.forename: Tingting
authors.initials: T
authors.lastname: Ma
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects; D000397:Air Pollution / Q000009:adverse effects; D001943:Breast Neoplasms / Q000473:pathology*; D003710:Demography; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects*; D015262:Xenobiotics / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D015262:Xenobiotics