Science Interviews


Thu, 10th Jul 2014

Saskia Sanderson - Gene testing issues

Saskia Sanderson, UCL

Listen Now    Download as mp3 from the show Issues for genetic testing

Kat:: Thanks to advances in technology, a day when we might each have our own personal genome at our fingertips is coming ever closer. But what can people do with this information, and what are the issues involved? To get to grips with this brave new genetic world, I spoke to Dr Saskia Sanderson from the Health Behaviour Research Centre at UCL and the Icahn School of Medicine at Mount Sinai in New York. To start with, what exactly do we mean by genetic testing?

Saskia::  So, genetic testing really ranges from single genetic tests for gene variants that we really know quite a lot about - a good example of that would be the BRCA1 and 2 gene variants that were strongly associated with risk of breast cancer - then you have other genetic tests for single gene variants which really, we use for research purposes where you're looking at single gene variants associated with a very slightly increased risk of a common complex disease like heart disease, lung cancer, that kind of thing.  But those kinds of tests have also for the last few years been available direct to consumer.

Kat::  So, to the general public, you can get one on the internet basically.

Saskia::  Yes, although that has recently changed.  There have been developments recently that have made that less available to people.  But I think we might be almost a moment in time where it’s less available.  I think it’s probably going to come back again.  We also have genetic testing for ancestry which a lot of people are really interested in at the moment.  So many people are interested in genealogy.  Actually, that is a very booming industry if you like.

Kat::  The kind of recreational genetics.

Saskia::  Yes, but recreational, very specifically about where did you come from, very specifically about that side of things rather than the disease risks side or this will help you about your health.

Kat::  It’s basically, “Am I a Viking?”

Saskia::  Yes, exactly that.

Kat::  And now, we’re starting to move to an era where we have the ability to sequence entire genomes.  People can have their whole genomes sequenced.  Is that something that’s starting to become more common and will it become commonplace in the future?

Saskia::  I think we’re certainly saying more and more of it obviously.  I mean, we know that of course, it’s only 15 years ago, it costs $3 billion and took 15 years to sequence the first human genome.  You can now do it for $5,000 and it takes a few days.  So, it’s certainly becoming clearly more commonplace.  It’s happening a lot more for research purposes.  Many people are having their genome sequenced now as part of research studies.  We’re certainly seeing more of it, but I wouldn’t say it’s commonplace.  We’re still a long way to go.  We’re still a long way from having that, all of us having our whole genome on a USB stick that we take to our doctor and carry around with us.  That’s not going to happen for a while, but more and more people are having it done.  In the UK, last year, we now have the launch of the 100,000 Genome project where there are going to be thousands of people within the NHS having their genome sequenced for both clinical and research purposes.

Kat::  So, it’s likely that in the future, more and more of us in the general public are going to have to grapple with quite complex genetic data.  We hear the language of genes in the headlines, “Gene for this, gene for that.”  People are going to have to start engaging with genomic testing and genetic testing.  What do you think are some of the kind of issues that are going to come up or are coming up already?

Saskia::  I think what you just said is one of the first things that we need to make sure that people do start – that we start getting across which is, there are no “genes for” anything.  We have variants within genes that affect how the gene works, how the protein product works and basically, it’s these variations in your DNA that affect your disease risk, affect how tall you are.  There aren't genes “for” heart disease.  There aren't genes “for” disease.  There are genes that do things and sometimes they work better and sometimes they work worse.  So, I think that’s obviously one of the things that we need to make sure that it’s a starting point.  That’s where we need to make sure people understand. 

Many people argue that genetic information is just one more piece of health information in the way that your blood pressure is information about your risk of disease and this is another piece of information.  I think in many ways that’s true, but I do think genome sequencing takes us to a whole other level where people are going to have to get their heads around a large amount of data.  That said, there is another important consideration which is that, I think we’re used to thinking about testing as a sort of one-time test.  What we may also sort of want people gradually to kind of get their heads around as well is that having your genome sequenced might be something that happens at one point and then it’s a resource.  It’s not actually something that you get all the results from in one go.

Kat::  “Here you are, off you go.”

Saskia::  That’s right.  This is you on your USB stick.  Actually, what might happen and what's probably more likely is that you do have your genome sequence but then that can be accessed at different times in your life and for different purposes.  So, then you access it perhaps when you're of reproductive age – thinking about having children.  Perhaps when it looks like certain diseases develop.  With different things in your life, different times in your life where different bits of your genome or looking for different things within your genome will be important.  So, it could also be helpful to start thinking about your genome as a resource rather than your genome sequence and sequencing of your genome, more as a resource rather than a test.

Kat::  We know that we’re a product of nature and nurture, that we have genes that they interact with our environment and the things that we do, our lifestyle.  So, when people get this kind of information, what do they do with it?

Saskia::  So, I think the question partly depends on what you mean by this information.  The research that we’ve been doing, we started about 10, 15 years ago, was looking at how people responded to getting genetic risk information about their risk of lung cancer.  So here, we’re clearly talking about something, a disease.  It very clearly has a strong environmental behavioural component – smoking.  But also, I think people know.  They say to us, “I know that my grandmother smoked 20 a day, maybe 60 a day until she was 80 and she didn’t die of lung cancer.”  And therefore, it’s not all behavioural.  It’s not all caused by smoking.  They know that something else going on and that thing could well be of course, your genetic risk is what you bring genetically to the table. 

We still don’t know very much about the genetics of diseases like lung cancer.  We still don’t know, but we know something.  We know a lot more than we did and we’re going to know more in the coming years.  So, I think that one way to answer that question is that people already have some understanding that disease is complex, life is complex.  And that maybe, by bringing genetics into the story, that could actually be a helpful thing because it is part of the story and to kind of ignore that or pretend that it’s not part of the story, even when it’s in the context of something that which is so clearly affected by your behaviour like lung cancer – smoking – that that may just be something that we have to deal with.

Kat::  For example, the more that we understand about our genomes and things like the risk of diseases like cancer, and is there a risk that someone is just going to go, “It’s all in my genes.  There's nothing I can do” or “Well, my granny smoked and drank like a fish and she was fine, so I didn’t need to bother.”

Saskia::  We say so much about this in my field.  It has this term of genetic determinism, genetic fatalism.  I have to say, we absolutely cannot find evidence of it when we do the empirical research, which we have done.  We give genetic risk information about lung cancer to smokers, albeit very small pieces of risk information that’s influencing your risk this way or that way of small amount.  There is no evidence that whether then we tell a smoker that they have a slightly lower risk of lung cancer than somebody else based on their genes that they then go out and say, “Well, it’s alright then I can smoke as much as I want.”  And similarly, when we tell smokers that they have a slightly increased risk of lung cancer, they don’t go, “Oh my goodness!  It’s all in my genes.  There's nothing I can do about it.” 

We’ve seen that in lung cancer.  Others have seen it in all sorts of areas.  We’re still at the beginning of research in this field but I have to say, nobody can find evidence of that so far.  And so, I do think it’s important for people to recognise and I think truthfully also, I think if I tell somebody, if I give somebody some genetic risk information and they go off and think that - that they go from thinking is safe for them to smoke or they go off and think that they're doomed - I've done a terrible job of communicating that information to them and so, clearly, it’s important we communicate the information well.  I have to say, across all the research studies that I've seen, I have yet to see a study where people have gone off and thought either of those things.  So, I think empirically, the evidence for that so far simply isn’t there.

Kat::  So, you can't use your genome as an excuse for not trying to live a healthy lifestyle.

Saskia::  No!

Kat:: That was Saskia Sanderson from UCL and the Icahn School of Medicine.


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