AsianScientist (Jun. 30, 2016) – Researchers in Japan have revealed the mechanism by which 1,2-dichloropropane (DCP), a chemical often used in cleaning liquids in the printing industry, causes bile duct cancer.
These findings, published in Scientific Reports, indicate a relationship between chronic exposure to chlorinated organic solvents and bile duct cancer risk in humans.
In 2014, the International Agency for Research on Cancer re-classified the chlorine-based organic cleaning agent into Group 1, or carcinogenic to humans. It was originally in Group 3, or not classifiable as to its carcinogenicity to humans.
This decision was based on a major public health incident in Japan. Between 1996 and 2013, there was an outbreak of cholangiocarcinoma, or bile duct cancer, among young printing plant workers with long-term exposure to very high levels of 1,2-DCP.
Although a relationship between the incidence of bile duct cancer and occupational exposure to 1,2-DCP had been previously suggested, there was no biological evidence to explain the delayed onset of bile duct cancer and the general risk of developing it.
The research group, led by Project Assistant Professor Yu Toyoda at the University of Tokyo Hospital Department of Pharmacy, carried out an exhaustive survey of the components of bile, and developed mouse models in which most of the liver has been replaced with human cells.
Their findings partially uncover the latent relationship between chronic exposure to 1,2-DCP and bile duct cancer risk in humans: one possible explanation is that when the chemical is metabolized in the liver, a potential cancer-causing substance is excreted into the bile.
As other hazardous substances may also be associated with the development of bile duct cancer by similar mechanisms, Toyoda hopes that this research may pave the way to understanding the mechanism of onset and development of bile cancer, a disease for which there are few effective therapies.
The article can be found at: Toyoda et al. (2016) Halogenated Hydrocarbon Solvent-Related Cholangiocarcinoma Risk: Biliary Excretion of Glutathione Conjugates of 1,2-Dichloropropane Evidenced by Untargeted Metabolomics Analysis.
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Source: University of Tokyo; Photo: Shutterstock.
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