Knowledge is power: Cancer and the genetic revolution
Dr Kat Arney a science information officer for Cancer Research UK writes about the genomic research that is already started to change the way we think about the cancer.
Imagine a time when everyone can be tested to see if their genes put them at a great risk of cancer, then have tailored lifestyle advice and screening to help prevent the disease. Those that do develop cancer receive personalised treatment, based on their own and their tumour’s genetic make-up, boosting their chances of survival with fewer side effects. We’re working to make this vision a reality.
In 2001, an international team of researchers announced that they had sequenced the human genome for the first time, reading the genetic ‘recipe book’ that controls our cells and bodies. It cost two billion dollars and took years. Today, scientists can read a whole genome in less than a week, and the cost is fast approaching £1,000. The next generation of DNA readers are roughly the size of a desktop printer and a million times faster than the devices that sequenced the first human genome. And curious people with a few thousand pounds to spare can even pay a commercial company to decode their own genome.
At its heart, cancer is a disease of our genes. It starts with faults (mutations) in our DNA – both inherited and picked up over a lifetime – affecting genes instructing cells when to grow and when to die. When these crucial instructions become corrupted, cells grow out of control and fail to die when they should, creating a tumour. Further gene changes enable cancer cells to start spreading round the body and become resistant to treatments such as chemotherapy, hormone therapy and radiotherapy. Our genes make us individual, from the way we look to our risk of developing different diseases, and it’s becoming clear that every patient’s cancer is as genetically unique as they are.
The recent explosion of technology and knowledge is now being turned on cancer, aiming to reveal its weaknesses and lead to more effective ways to diagnose, treat and prevent the disease. When Cancer Research UK formed in 2002 from the merger of two existing cancer charities, our director Paul Nurse remarked that “combining forces will give us the impetus to turn the potential of the genetic revolution into the reality of new drugs and treatments”. The cancer research community finally has the tools in our hands to do this.
We already know about some of the faulty genes that drive cancers and ways to target them. Glivec (imatinib) – a drug that has completely changed the picture for people with a certain type of leukaemia – targets a specific gene fault. The breast cancer drug Herceptin (trastuzumab) targets cancers with extra copies of a gene called HER2, and there are many more targeted agents coming through the pipeline all the time. But the big challenge is finding out who will benefit from these treatments – although they’re precision weapons, they’re also very expensive and will only work in patients whose cancers carry the particular fault that’s targeted by the drug. And at the moment, many targeted drugs only offer relatively modest improvements in survival – something that is likely to change as we understand more about the underlying genetic landscape of tumours.
Prime Minister David Cameron recently announced a major new initiative, earmarking £100 million to introduce large-scale DNA sequencing for up to 100,000 cancer patients and people with rare diseases. This is a welcome pledge by the government that could help to put the UK at the front of the genome revolution, although we’re still waiting to hear the exact details of what the project will involve. But this isn’t the only thing that’s going on, and Cancer Research UK is leading the charge into the new genetic future.
Over the past couple of years, we’ve been investing heavily in projects designed to bring the fruits of genetics research to benefit people with cancer. Through our Stratified Medicine Programme we’re working together with the government’s Technology Strategy Board, AstraZeneca and Pfizer to find out how to bring routine genetic analysis of patients’ tumours into the NHS. The study is testing tumours for the presence of particular mutations that make a patient’s cancer more susceptible to certain drugs, which could lead to a step-change in the way cancer is treated in the UK.
Along with hundreds of scientists around the world, we’re part of the International Cancer Genome Consortium, or ICGC for short. ICGC will map the genetic faults in 25,000 tumour samples from patients with 50 different types of cancer, including breast, bowel, ovarian, pancreatic and lung cancers. Cancer Research UK is leading the projects uncovering the genetic secrets of prostate and oesophageal cancer. And there’s also our Genomics Initiative – nine high-tech projects designed to answer some key questions about the genetic makeup of a range of cancers, from bowel cancer to rare childhood brain tumours.
But while these projects are all producing valuable information about cancer, the amount of data they produce is staggering. Coping with this data explosion is a major challenge. There might be thousands of genetic mistakes in a cancer cell, as their genes tend to be very messed up. So how do you distinguish the handful of important ‘driver’ mutations that are fuelling a cancer from those that are just along for the ride? And there’s another twist –scientists at our London Research Institute recently discovered important details about the extent to which cancers can evolve and mutate within an individual patient as the disease spreads and becomes resistant to treatment.
Despite these challenges, genomic research is already starting to change the way we think about cancer, and the pace of progress is accelerating at an unprecedented speed. This year our researchers in Cambridge carried out a groundbreaking genetic fingerprinting study on nearly 1,000 breast cancers, showing that they can be grouped into ten different types with distinct characteristics. This discovery has big implications for how women with these different subtypes of cancer are treated.
As this kind of research extends into other cancer types, we’re moving away from the idea of a breast cancer, bowel cancer, lung cancer and so on, and towards dividing up cancers according to the gene faults that drive them. This greater precision should lead to more effective treatments for patients in the future, ultimately helping more people to survive.
Dr Kat Arney is Science Information Manager at Cancer Research UK and writes for the charity's award-winning Science Update blog.
The views and opinions expressed in this article are those of the author(s) and do not necessarily reflect the official policy or position of The Information Daily, its parent company or any associated businesses.