IARC 50th Anniversary Conference
Systems perspectives of the exposome
Dr Paolo Vineis - Imperial College, London, UK
What is an exposome?
Yes, this word was coined years ago by Christopher Wild who is a director of IARC because he thought that a lot of effort had been put into the genome research, and of course we got a lot of knowledge from genome research, but he noticed and he raised the issue that it is likely that most cancers come from environmental exposures, not really from inherited changes in our DNA. So he said why don’t we put at least as many efforts and resources into the study of environmental exposures. So he developed this concept of the exposome.
What are the most important compounds of the exposome?
Well the idea is that with the current technologies you can look at virtually all exposures, which is probably not possible, frankly, but you can look at many more exposures than we usually consider, like smoking or irradiation. We have studied for years smoking and irradiation and asbestos but there is much more in the world that surrounds us and the environment. So the word exposome means that we should look at many more exposures, some of which are chemical exposures, others are microbiological exposures, and we can do that both refining measurements in the environment, for example with sensors, or by measuring things in our blood or in our tissues with omics technologies.
Which exposures should we focus on?
Now we are working on air pollution but there is much to do about diet, for example, because the tools that have been used so far were questionnaires about dietary habits. Now there are powerful approaches like metabolomics to look at metabolites in our blood or urine coming from dietary exposures. So we can answer with greater accuracy to some of the open questions – what are the dietary constituents that can increase the risk of cancer or protect us from cancer?
What exposure components should we look out for in future?
There are several. I would say that we still know little about many environmental exposures coming from the thousands or tens of thousands of chemicals that are in the environment that are not tested usually for their potential toxicity. So I would consider environmental exposures as a priority and also diet is still important, including residues of pesticides and other chemicals.
What is your take-home message?
One take-home message is that cancer can be prevented. So doctors should be involved in the effort to educate their patients, for example, and relatives of patients, about what you can do in terms of primary prevention which is not simply avoid smoking, which is quite important, but there are several different things that can be done. As IARC has said several times, about 40-50% of cancers are preventable. And another quite important take-home message is that cancer is increasing in low income countries and middle income countries. This is dramatic because they do not have the resources to tackle the cancer epidemic. So this is again a very important reason to put efforts into prevention in those countries. Because IARC speaks to the world, it doesn’t speak only to developed countries.
What do you feel requires urgent attention?
The spread of smoking to developing countries, to low and middle income countries, and perhaps also the spread of a certain kind of Western dietary habits and obesity. So the Westernised food and obesity also require a lot of attention, the spread to low income countries.