Emma Smith - Cancer genomes

11 May 2016

Interview with

Emma Smith, Cancer Research UK

Kat - It's been hailed as a 'milestone' in cancer genetics: researchers at the Wellcome Trust Sanger Institute in Cambridge have sequenced and analysed the entire genomes of more than 500 breast tumours, revealing exciting new clues about the origins of the disease and how to treat it more effectively. I caught up with Dr Emma Smith, Science Information Manager at Cancer Research UK, to find out what they discovered in there.

Emma - They found entirely new genetic faults that have never been found before. They also looked at interesting patterns of genetic mutations. I think this is something that's really interesting. For certain cancers like lung cancer, it's often linked to tobacco smoke and smoking. We know in that case particularly what's causing the DNA damage. It's chemicals in the smoke. But for breast cancer, nobody has really understood today what's causing the genetic mutations to crop up, why would they suddenly appear in the cells. That's what these results produce, some really intriguing clues into the underlying biological processes that could be going wrong to drive the disease in the first place.

Kat - So, in terms of looking at these cancer genomes, all the sum total of DNA in these tumours, it's like poring through hundreds of recipe books looking for every single typo in every word in every recipe. How messed up were these cancers genetically speaking?

Emma - And they did find that the mistakes were concentrated in certain genes, but they also showed that actually, every person's cancer was really quite individual and unique to them. So, every person's cancer is a unique genetic tale, documenting their build-up of genetic mistakes over time. it kind of really emphasises the importance of moving towards personalised or tailored medicine, moving away from this whole idea of 'one cap fits all' treatment that everyone with breast cancer should be lumped together and given the same kind of treatment because everybody's cancer is really very individual to them.

Kat - What exactly does that mean? How do you take this information that you found in the genetics of someone's tumour, their genetic signature of their cancer and go, "Okay, you need this and that treatment"? How does that actually work?

Emma - There are lots of drugs out there that have been developed that specifically target faulty molecules. But the trouble is, who do we give these treatments to? We know certain groups of people that respond to them, but we don't really understand who's actually going to benefit from, who's not. And also in the past, cancer treatment has been very much guided by what kind of cancer you have. If you have breast cancer, you're given this treatment versus another type of treatment for lung cancer. But actually, doctors are moving from that now and viewing cancers as being determined more by their genetic faults. And actually, treatments in the past that have worked for types of lung cancer could work for types of breast cancer, could work for types of brain tumour because it's all about the shared genetic mistakes that are fuelling that cancer. If we can get treatments that particularly target them, A. they might be more effective, and B. they also might be kinder and spare healthy tissue because they specifically home in on cancer cells.

Kat - In terms of the types of damage, were there specific - I've heard them described as scars in the genome - specific patterns of damage and do we know what might have been causing some of them in these breast cancers?

Emma - It's a really interesting question. Some of them, they do know. For example, women with faults in their gene called BRCA1 or BRCA2, they already know that they are defects in the molecules that fix DNA and they leave these very characteristic scars on their DNA. They saw this and they saw that actually, BRCA1 and BRCA2 had very different footprints which is really interesting. They didn't know that before. Another pattern or mutational signature if you want, they found was caused by a molecule called APOBECs. I love APOBECs, they're really interesting. They were first discovered through HIV research and research into the immune system. They're actually very important for normal healthy functioning immune system. But if they go haywire like they can do in cancer, suddenly they're introducing mutations into their DNA, left, right and centre. If a mutation happens in a key gene, that's when you can get cancer developing so some really interesting patterns or mutational signatures. They also characterise some that they still don't know what's causing them. So, this has really opened whole new field of biology that I think is going to be really exciting in the next few years.

Kat - This is a huge amount of data, a huge amount of information to scour through, but it's still one type of concept. Are there other researchers who are looking at other types of cancer? Is this the way that cancer research is going now?

Emma - Absolutely. the introduction of personalised medicine, of sequencing genomes, looking for particular patterns in mistakes in genes, and then trying to tailor treatments accordingly is taking off in a big way in different types of cancer. For lung cancer, we've got the big stratified medicine programme now, being rolled up in the NHS to try and match treatments better to lung cancer patients. It will happen across different cancer types as well. But I think what's really exciting is that these results from breast cancer might well be applicable to other types of cancer as well. The same underlying biological processes might be driving other types of cancer that we don't know about yet. So, using this kind of research to fuel the discovery of new treatments or to better tailor treatments might well be applicable across the board.

Kat - That was Emma Smith from Cancer Research UK

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