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A vaccine for cancer? -

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Robyn Williams: Cancer, like schizophrenia, is hundreds of diseases. So how could it be possible to develop a vaccine to combat them all? Well, that's what Stephen Johnston is trying to do in Phoenix at the Arizona State University. But why?

I'm sure you've been told this before, but a vaccine for a cancer is okay but for most cancers sounds wildly ambitious. How come?

Stephen Johnston: Well, actually all cancer vaccines to date, except for the ones against infectious agents like HPV and Hepatitis B, have been therapeutic. They've been after the fact. And that's probably why they haven't worked. So we just decided to take a little different approach, and that is get the vaccine before you would get the cancer, just like an infectious disease. It's a really simple concept.

Robyn Williams: But given that there are so many different kinds of cancer, how can you have a universal agent?

Stephen Johnston: Because all cancers, it turns out, make some of the same mistakes. There's enough overlap between them that if you find the composite of all the things that they have in common, which we think probably will be less than ten things, and you put them all together, you will anticipate any cancer that would turn up.

Robyn Williams: What particularly are you homing in on at the moment?

Stephen Johnston: They're called neoantigens. What they are is because cancers, in order to be cancer they have to relax all their quality control systems for the proteins they make, they end up making some really junky proteins, and those are very immunogenic. And so we've homed in on these pieces of junk peptides that they make.

Robyn Williams: So if you hone in on that, how would your vaccine actually work?

Stephen Johnston: So we take ten of these junk peptides and we put those together into a vaccine. And we would just administer that vaccine before anyone would have those tumours. It has to be before. And then once you start the tumour your immune system has already seen the antigens that the tumour would present and would kill it. Just like it does for an infection.

Robyn Williams: The great thing about the immune system is obviously you can't have an unlimited number of agents that would knock any germ or any infection or any malfunction, but instead you can get some sort of code as to what it is and the body goes off to manufacture the right antigen, if you like, and say 'here is the weapon that would work'. But you've got to be in time.

Stephen Johnston: That's right. It has to be before the tumour presents that antigen to the immune system, because that's why therapeutic vaccines haven't worked. Once the tumour presents that antigen it basically starts to turn the immune system off to those same antigens. And that's why infectious disease vaccines only work generally if you give it before the tumour. If you try and give somebody a vaccine after the infection's started, if almost never works.

Robyn Williams: Have you got anything that you can actually put into experimental trials yet?

Stephen Johnston: Yes, we've been through pre-clinical trials, so that's in animal models, and have our candidates lined up. So our next step is to put it into a dog, it's real cancer prevention in dogs.

Robyn Williams: But then what do you do, just wait for the dog to get something like a cancer and find out that it doesn't, or do you induce cancers in some way?

Stephen Johnston: No, this will be a real test, so we'll give it to dogs that don't have cancer and then wait to see whether the vaccine prevents cancer. Now, we actually have invented another thing, so we've invented a system where we take a drop of blood and tell whether an animal has a cancer much, much earlier than waiting for a standard diagnosis.

Robyn Williams: So how is this experiment going so far?

Stephen Johnston: So the dog trial we hope to start this spring. And we've got the immune signaturing technology in place, so that it should shorten the trial.

Robyn Williams: I must say, Stephen, on your door you've got an editorial from Nature saying that this work should not happen, plus your reply. What did you think when you opened the journal Nature and saw yourself being maligned in this way?

Stephen Johnston: I sort of knew it was coming, because the community generally thinks that this not worth pursuing, because it can't be done. It's interesting, of all the…first they said it couldn't be made, the vaccine couldn't be made. Generally the community now says it may be able to be made but you never could test it in enough time and at low enough cost to make it practical. And that's a legitimate concern, but I think we've invented ways to get around that. Our contention is that it's easy to say not to try something like that, but I think it's actually a fault of the community. We're the only ones trying to do this. Somebody should have tried to do it, even if it doesn't work, just because the benefit would be so great if it happened to work.

Robyn Williams: And when you replied to the journal Nature in a letter, what was the response from your colleagues around the world?

Stephen Johnston: Most of them said it was a good thing I replied, but I think most of them weren't convinced that it's still going to work.

Robyn Williams: Do you mind being an outlier?

Stephen Johnston: No, I mean why go into science if you just do the things that everybody expects to work? So I teach my students, I say always look for two things to do if you're a scientist. One, look for the infinity experiment, that is an experiment that no-one else has ever done before so you can make an infinite contribution. And then the other thing is look for contrary experiments. If everybody's going off and doing certain things then you might as well look for something that is the opposite of what everybody else is doing and just do it anyway.

Robyn Williams: And of course the payoff is fantastic if you're right.

Stephen Johnston: If you're right. It's hard to get funded, but if you're right the payoff's good.

Robyn Williams: Stephen Johnston is co-director of the Centre for Innovations in Medicine, Arizona State University.


Guests
Stephen JohnstonCo-Director
Center for Innovations in Medicine
Arizona State University
Phoenix Arizona USA

Further Information
Stephen Johnston at The Arizona State University

Credits
PresenterRobyn Williams ProducerDavid Fisher