Trial Information

Environmental and Biological Monitoring Pilot Study for Polycyclic Aromatic Hydrocarbons in Linxian, China

The overall goal of this project is to determine whether polycyclic aromatic hydrocarbons (P
AHs) or acetaldehyde are contributing to the high rate of esophageal cancer in Linxian,
China.

Esophageal cancer is one of the most fatal cancers worldwide and Linxian, China has some of
the highest rates of this cancer in the world. In the United States esophageal cancer causes
approximately 14,000 deaths each year. It is the fourth most common cause of cancer death in
black males and the eighth leading cause of cancer death in men of all races. The
prevention and treatment of esophageal cancer within high risk groups continues to be
limited by our inability to identify specific etiologic agents.

Human exposure to PAHs, including benzo[a]pyrene (B [a]P) is associated with increased rates
of skin, lung, esophageal and gastric tumors and also with an increased mortality from
causes related to atherosclerosis. Preliminary results from histologic and food analysis
pilot studies supports the possibility that the high rates of esophageal cancer in Linxian
may be related to long-term, high level exposure to PAHs via inhalation of air-borne
pollution and ingestion of food cooked with soft coal.

Exposure to acetaldehyde could also be an etiologically significant exposure in Linxian.
Acetaldehyde is a carcinogenic metabolite, and small quantities of ethanol where recently
found in homogenized Linxian food samples. The Salaspuro laboratory at the University of
Helsinki has demonstrated that oral bacteria can produce acetaldehyde from food containing
similar small concentrations of ethanol, so such acetaldehyde exposure could be
etiologically significant in Linxian. Genetic polymorphisms, particularly those involving
alcohol and acetaldehyde dehydrogenases, may also influence the effect of this exposure.

To assess the association of PAHs and acetaldehyde with the high rate of esophageal cancer
in Linxian, China, we plant o analyze samples of food for the presence of PAHs, ethanol and
acetaldehyde, samples of blood for Hb and DNA adducts( markers of long-term PAH or
acetaldehyde exposure), samples of urine for 1-OH-Pyrene glucuronide (a marker of short term
PAH exposure) samples of saliva for acetaldehyde and samples of coal for characteristics
that may be associated with increased carcinogenesis. We will also administer environmental
questionnaires that will include questions about the type of fuel used for cooking and
heating, the location and types of stove and/or heating units, and the time spent cooking.