Cancer, How Cancer Spreads, and Complementary Therapies
In this show, Fran Balkwill and Andrew Wyllie join us to discuss cancer, how cancer and tumours spread and how the body responds to cancer, and Toby Murcott talks about methods of testing the effectiveness of complementary medicines. Also, Chris Smith reports on all the top science news live from the AAAS in Washington.
In this episode
A Portion of Chips With Hepatitis Vaccine
A new version of the humble potato may protect thousands of people each year by giving people a dose of the hepatitis B vaccine. Hepatitis B is a virus that infects millions of people annually, and nearly one million people die worldwide from liver problems caused by the virus. It doesn't kill many people in the UK because there are safe and effective vaccines. But in the developing world, vaccines that could be given by mouth, such as the vaccine for polio, would be much more effective as there would be no need for needles and keeping the vaccine cold. While digging around for a method to create an edible hepatitis vaccine, scientists unearthed the idea of using potatoes. The genetically engineered potatoes carry a gene that makes part of the hepatitis B virus. When people fed with the vaccine-filled spuds were compared with those given normal spuds, they found that about 60% of people who ate their engineered spuds had an immune reaction against hepatitis. An immune response to hepatitis B is measured by the number of antibodies in the blood, which are made when the body senses an alien protein. Although this needs more work and testing, it certainly looks like potatoes might be a promising way to deliver vaccines in the future.
Alien Ant Invasion in Hong Kong
Scientists in Hong Kong are considering introducing ant eaters to control a recent outbreak in alien ants. The ants, called red fire ants, are thought to have arrived from South America in imported pot plants. Ant hills were first spotted in fields and are now popping up all over the city, including Disney Land Hong Kong. Although red ant bites are not usually fatal, they can be very painful. Some people are allergic to ant bites, and a nasty nip can trigger a dangerous allergic reaction. As these ants have only just been introduced, this may be the perfect time to stamp on the invasion and stop the ants spreading any further. One of the solutions suggested by the Hong Kong government is an army of anteaters. This natural predator would wander the streets and hoover up the ants. Whether this strategy will work is yet to be seen. Other examples of biological control, such as the cane toad in Australia, have ended in disaster.
Why a Bad Dress Rehearsal May Be a Good Thing
Anyone ever been on stage or in a band? Well, you may know that sinking feeling when the last rehearsal just goes horribly wrong, which changes to elation when it's all alright the following night. Now scientists in New York have found scientific evidence that not only does sleeping on it help you perform better, but the worst dress rehearsals make for the best performances - at least if you're a zebra finch. The scientists took recordings of young finches as they learnt to sing by squawking along to adult songs. The team then developed clever computer software to analyse the learner songsmiths, to work out how much progress they'd made. Apparently, when the birds first wake up in the morning their singing isn't really up to scratch, and in fact they are much worse singers than they were the previous day. But after a morning of singing, they end up better than they were the day before - a case of one step backwards two steps forwards. Intriguingly, the birds who are the worst singers in the morning turn out to be the best singers by the time the baby birds grow up. Previous research has found that the parts of zebra finches' brains that control singing are active during the night, so it looks like sleeping on it helps the finches to learn in the long term, even though they might sound worse during the rehearsals. The researchers think that the time is right for a detailed study of the effects of sleep on human babies' learning, because the development of birdsong is quite similar to the way humans learn to speak. Though that may depend how bird-brained the babies are!
- Live From The American Association For The Advancement of Science
Live From The American Association For The Advancement of Science
with Dr Chris Smith, in Washington
Chris - I'm in Washington this week for the AAAS, which stands for the American Association for the Advancement of Science. I'm getting to meet lots of people doing some amazing research over here in America. This evening, I'm going to tell some rather worrying information about whales; talk about work in Mexico where scientists are effectively x-raying a pyramid; some news about avian flu; and how a new type of fishing line might put an end to 'the one that got away' stories.
Kat - So what's the deal with the whales?
Chris - Whales are very much auditory creatures. They communicate using infra - sound, which is very low frequency sound waves that travel well through water and can be heard by other whales thousands of miles away. I spoke to researcher Dr Christopher Clark from Cornell University. He's finding evidence that the noise mankind is making in the environment is causing major havoc for whales. Historically, whales were able to find mates hundreds of miles away, just by listening out for them. Now their dating game is restricted to perhaps twenty to a hundred miles because the racket we're making in the sea means that it's much more difficult for them to hear each other.
I asked him whether whales have changed their behaviour in order to compensate for this because birds living in cities have been shown to increase the frequency of the notes in their songs to compensate for all the noise around them. Apparently whales have done the same thing, but by lowering their voices by an octave to an octave and a half. But they are already at the extent of their voice range, meaning that they won't be able to change much more. This is a bad thing, because whales not only use their voices for the mating game, but also to tell others where food is and when predators are nearby. This might cause their numbers to go into further decline.
Helen - Whales are also declining because of hunting. Hearing a whale sing under water is the most amazing thing, and so I really hope there isn't too much more bad news for them.
Kat - What about the pyramids?
Chris - Well it relies on a cosmic particle called a muon. When the earth is bathed and bombarded with radiation coming in from outer space, which happens on a second by second basis, the cosmic radiation strikes our protective magnetic field and most of it gets removed so that it doesn't come into the earth's atmosphere. This is why you get the Northern Lights. However, some particles get through, interact with our atmosphere and produce something a bit like a giant electron. This charged particle is called a muon. It doesn't live for very long; literally just millionths of a second, but it moves incredibly fast and is very penetrating.
X - rays work by passing high energy light waves through the body. When they hit something dense like bone, they are absorbed. But when they hit soft tissue, they pass through more easily. This lets you build up a picture of the internal structure of the body. Muons can be used to do exactly the same thing, but for rocks! In other words, they can pass straight through buildings and other dense things, but some are mopped up on the way. So, just like an x-ray, they can be used to to work out what's inside dense structures like pyramids.
In this story really centres on Mexico. There is a structure in Mexico, which is actually Mexico's leading tourist attraction, called the Pyramid of the Sun. It dates back about 2000 years, but that's pretty much all we know about it. When the Aztecs arrived the pyramid had already been there about 600 years, but it was built by a civilisation that we known nothing about. The people who lived there left no written record of their activities; just pyramids. No-one knows what's inside the Pyramid of the Sun, but owing to its archaeological significance, it's also not appropriate to dig it up. But if we could find out what's inside, we might discover something about the people that built it.
So scientists have decided to give it an x-ray, with muons. Conveniently, there is a natural tunnel underneath the pyramid. By placing a detector in the tunnel, muons from the atmosphere which pass through the pyramid can be counted and used to build up a profile of the inside of the pyramid.
for instance, if the pyramid is solid, then you will collect far fewer muons than if it's got holes in it. Scientists can work out what's inside the pyramid by looking at where the muons have come from and their respective scatter patterns, meaning that scientists don't have to dig it up. If there is something inside, researchers can work out what it is, and where it is, without having to do devastating damage to the structure.
Mandy - What are they hoping to find? Is there any indication of what might be inside there?
Chris - There is a bit of information, because there's another pyramid just down the road called the Pyramid of the Moon and this one has been excavated. Inside, they found a burial chamber. As we don't know much about these people, if we could identify the burial chamber, we could potentially extract DNA if the occupants are well enough preserved. This could be used to work out where these people came from, who they were, what kind of diseases they might have suffered from, and also where they may have ended up. It would also help us to track down where mankind were spreading to at this point in history.
Kat - Is there anything else we can do with muons?
Chris - Yes, there is. America is worried about people trying to attack them. They are trying to work out how they can use muons to find out what is hidden in the backs of lorries. People are worried about the shipping of radioactive isotopes, as they could be used to make bombs. Obviously, there needs to be a way of stopping the lorry driver from being fried, so if someone is trying to transport radioactive isotopes, they will want to keep it in a heavy container made of something like lead. Muons can't pass through lead either, so the detectors will pin point any things in the lorry that are particularly dense or heavy. These could potentially be containers holding radioactive materials. Mandy - So this could potentially revolutionise security.
Chris - I'm just hoping that it won't slow down customs any more!
Kat - So what's this final story on fishing tackle?
Chris - 'The one that got away' graces every fishing story down the pub, and anglers often blame their equipment, but this could soon be a thing of the past. A research group from Ohio that have come up with a new polymer that can be incorporated into fishing line to pin point weak spots. The idea is that when your fishing line becomes stretched or distorted, it glows bright green. The only slight downside is that you need a UV (ultraviolet) lamp to see it glowing! The effect is produced by a chemical called phenylene-ethylene-oligomer, which is incorporated into the fishing line. As the chemical structure of the line becomes distorted by stress or tension, the optical properties change, and the line fluoresces under UV. The team are now working on another way to make the line glow in day light, helping fisherman to know when it is time to change their tackle. It could also be used to make tamper-proof coverings. If you have a sealed product and are not too sure if someone has injected something into it, if you shone a UV light over this material, any needle puncture points would glow green. So it has a non-fishing use too.
- Complementary Therapies
with Dr. Toby Murcott, science writer and broadcaster
Kat - You look at whether we can look at complementary medicine in a scientific way. Can you tell me what your book is about, and what gave you the idea to write it?
Toby - The book is not about whether complementary medicine works, but how do we know whether it works or not. I think that this is a more important question. At the moment, we have no real way of testing these methods to see if they do what they claim they do.
Kat - What first got you interested in this question?
Toby - I first became interested when an old cat of mine became ill. I took him to the vets and was told that his kidneys had failed. Rather than have him put to sleep, I decided to take him to a homeopathic vet. Homeopathic remedies don't contain any active ingredients, so I knew that my cat wasn't going to be in any harm. The homeopathic vet asked me if the cat had lost his fur at any time, to which I said yes. The vet called this 'angry kidneys'. If my cat took some pills for the next few weeks, I was told his fur would start to fall out again as the 'anger' from the kidneys was drawn out. This is indeed what happened and the cat went on to live another year rather than the two weeks predicted by the first vet.
This anecdotal evidence tells us absolutely nothing. We couldn't take half a cat and give that the homeopathic remedy while leaving the other half as a control. This problem stuck around in the back of my head. As I started talking to professors and doctors that had looked into it, I realised that all the arguments for and against complementary medicine are based on whether they work or not. No-one understands how to look at and test them properly.
Kat - We have Professor Fran Balkwell in the studio. Would you please tell us how you would test a drug in a clinical trial?
Fran - For a cancer drug, the first thing you do is a phase 1 clinical trial. That is done on patients for which there is no other option. Their cancer will be very advanced and there will be no other treatment for them. At this stage of the trial, you look for how toxic the drug is and not whether it has any effects. At phase 2, you try to give the drug the best chance of working. Scientists will look for responses such as tumours shrinking. If there is an effect at phase 2, you move onto phase 3, which is randomised. You give one group the best treatment currently available and you compare it with the new drug that you're testing. After testing it on a large number of people, the results will indicate whether the drug is really having an effect.
Kat - So that's the scientific view. Toby, how do you propose this model be used to test complementary medicines?
Toby - I think it is best to use an example like physiotherapy first. It is widely used and has good effects. If you try to treat physiotherapy as a cancer drug, you immediately run into some problems. Firstly, the treatment is individualised. If the physiotherapist applied the same treatment to everybody, it wouldn't work. They apply the same principles, but it is dependent on how quickly the patients get better, their particular problem and their own musculature. Secondly, part of the role of the physiotherapist is to develop a relationship with the patient. If they develop a good relationship, chances are that the patient will get better more quickly. The patient is more likely to do their exercises than if they don't like their physiotherapist. This interaction of individualised treatment and the relationship automatically makes things complicated. This is not to say that it couldn't be put through clinical trials, it is just that it is not as simple as testing a straightforward drug. This is the same for testing things like acupuncture and reiki. No useful results will come out of it. What we need is a new type of protocol that takes into account the treatment as a whole.
Kat - Do you think that complementary medicines are just placebos?
Toby - Any doctor will admit that the placebo is an important part of the healing process. It has even been enshrined in some versions of the Hippocratic Oath, which says that 'a kind word and a bit of care can be as effective as the pharmacist's drug or the surgeon's knife'. We can't discount the placebo. It definitely makes people feel better. Placebos can come in the form of pills that have nothing in them, or there can be a context placebo effect. This can be when people feel better by, say, going to the doctors. Just doing something about your illness can make people feel better.
Andrew - We have some medical students that have to spend a day outside of the health service in an area concerned with health care. Many visit the local Chinese doctor and other complementary medicine practitioners. What they all say is that the practitioner was a very good psychologist, very good with the people that came in, good a dealing with stress and good at giving their time.
Toby - Yes, I think that some of the treatments have genuine therapeutic effects, even if some of the others are crazy. In most of them, it is something about that relationship. I think everyone involved in health care might be able to learn something from this.
- Why does cancer tend to be more common in older people?
Why does cancer tend to be more common in older people?
It's a very good question and a very astute observation. It really has to do with the fact that many different genes need to be altered by their contact with whatever it is in the environment that causes cancer in the first place. It's seldom that any single gene defect is involved in cancer. People think that it takes at least six to eight genes, but it is probably many more. They must all be altered together in the same cell before you get the change in behaviour that we would call cancer. The chance of getting all these changes at the same time in one cell is actually very low, but it increases with age.
- My dad died from cancer. What are the chances that I or my brothers will get cancer? Are ...?
My dad died from cancer. What are the chances that I or my brothers will get cancer? Are ...?
There are some families that have a very strong history of cancer, but these are mercifully very rare. The majority of cancers are sporadic. There are probably some influences that can give you a slight increase of cancer risk, but inherited cancers themselves are actually very rare.
- How do cancers run in families?
How do cancers run in families?
(Kat) If cancer is hereditary, it tends to be the same type of cancer or a group of similar cancers. (Andrew) Breast cancer in families is a known phenomenon. If the same cancer turns up in close relatives, there are some tests that can be done to find out who is most at risk. I think in your case, the cancers don't fall into any pattern that I can recognise as being inherited. The difficulty with sorting all this out is that people who share the same environment sometimes share exposure to the same carcinogens. (Fran) Cancer is such a common disease now that about 1 in 3 people will experience cancer at some time in their lifetime. Overall, the odds experienced by your family are not as extreme as they may seem.
- Is rheumatoid arthritis a risk factor for breast cancer?
Is rheumatoid arthritis a risk factor for breast cancer?
That's a very good question and I am sorry to hear about your arthritis and cancer. I don't think they are connected. The thing about cancers that are caused by inflammation is that they tend to occur in the sites where the inflammation occurs. For example, people that have inflammatory disease of the bowel tend to have an increased instance of bowel cancer. Your breast cancer is probably an independent event. There is no evidence that I know of that that shows people with rheumatoid arthritis having an increased risk of breast cancer.