The liver acts as a filter that cleans our blood, but some substances (chemical pollutants in the environment, in the food, heavy metals, etc.) can accumulate and cause several diseases.
One example is the case of PCBs: they might be present in food, promote carcinogenesis, and have been found into the liver of several animals and humans (one, two, three).
I'm asking to get more information about this topic: which substances are these, where do they come from, and how to get rid of them if there's a way.
I'm sure the field of human exposure to environmental chemicals is very wide but people here on SE are really good at giving informed, educational answers.