Whilst there are many different types of cancer, do we know what triggers off the process (i.e. when 'normal' cells turn into rogue / cancerous cells)?
There are two very important points there. One is that yes, there are many different diseases - in other words, cancer in different sites can be caused by different things and has different degrees of threat to the patient. So, it is very much a collection of many different diseases which have in common the cells behaving anti-socially and selfishly. But the causes, however, can be very varied and numerous.

At one extreme, we can inherit a damaged gene from our parents which increases the risk of a particular type of cancer. Well known examples of this are some of the genes that predispose a person to breast cancer, the so-called breast cancer susceptibility gene - those can increase the risk of subsequently contracting cancer, but environmental factors, also contribute a lot to gaining cancer and of these, by far the most notorious is cigarette smoke.

There are others, like asbestos and the recent one that's had a lot of publicity in the news is Sudan 1, the dye that's caused all the problems, but a range of environmental factors such as tobacco smoke, ionising radiation - all these are things which can increase or can trigger cancer.

To understand that, it's necessary to think of cancer as a multi-step process - lots of changes accumulate in a cell before it can become a full cancer. So, cancer arises by accumulation of a whole series of small changes in the cell and are actually changes in DNA, so when we're thinking of cancer, it's as a disease of damaged DNA, the genetic material that we have in all of our cells that tell them what to do, and accumulation of many little 'damage events' in the DNA can cause a cell to evolve along the pathway to cancer. That's one of the themes that the Science Week exhibits will illustrate.

Are more and more people now getting cancer or have we got this impression simply because of better communication mechanisms?
There isn't one simple answer to that. Cancer's been around for a long time, and again, an exhibit in the Science Week will show that the ancient Egyptians described cancer and we also know that it's been around before humans evolved.

A key question is 'has the incidence increased?' and here again, there are several ways of looking at it. One is that, for some cancers the incidence has undoubtedly increased, so the commonest cancer, lung cancer, is common because of smoking and no matter how much the tobacco industry try to confuse the facts, there's a very clear correlation that the increase in lung cancer went up with smoking and it's coming back down as people quit smoking and while it's falling in Britain, as fewer people smoke than used to a few years ago, it's rising in countries where smoking is on the increase.

There are also cases where there is an increase and we don't know why. Cancer of the gullet, the oesophagus - that's increasing and there have been several high profile cases recently such as the actor, John Thaw. But, in that case it's not clear why the incidence is increasing - it's one of the fastest increasing rates in the Western world so it's recently overtaken stomach cancer, which again, for reasons we're not entirely clear on, is coming down. We can speculate, but we don't really know the reasons for those changes. So, there are cases where we can say yes, the rate is changing, undoubtedly changing, but there are other cases where it's more difficult to be certain.

What are the most common cancers in the Western world?
Well, lung cancer for one became a huge epidemic because of smoking. Other common cancers are breast cancer, though in Britain, the death rate for breast cancer is falling and that's a point that we should not lose sight of - there is progress in some cancer.

Colo-rectal is another very common one and one thing that we're trying to do in this institute is find ways of detecting it earlier to make the treatment success rate higher. Obviously, with most of the common cancers, the earlier you catch it, the easier it is to treat successfully and so much of our effort goes into trying to improve early diagnosis of cancer. One cancer that would be much higher if there wasn't an already effective means of fighting or preventing it, is cancer of the cervix of the uterus, and that's a cancer where most of the deaths are prevented by the cervical smear programme - that actually saves at least 1000 lives a year in Britain.

Finally, if prevention is very much better than cure, what should we be doing in terms of our lifestyles to try and avoid getting cancer?
There are a lot of common sense things that people can do and by far the most important is don't smoke - that message can't be said too often. It really does account for an enormous proportion of cancer burden and leads to an enormous proportion of cancer deaths and that is a preventable problem. Cigarette smoke is singularly the worst single cause of cancer.

There are other things, with regard to cancer of the cervix, which is a case where early detection can make major benefits, so cervical smears can help prevent that - the incidence of cervical cancer is rising largely because of sexual behaviour (it's largely caused by a sexually transmitted virus) so once again, prudence can be beneficial in preventing that one.

There are other things, though, such as a simple healthy lifestyle - there's some debate over the extent to which obesity is a risk factor, so it's probably not a bad idea to try and avoid obesity in principal. And, I think there's growing evidence that intake of fruit and vegetables protects against cancer. The antioxidants in fruit and vegetables prevent the sort of damage to DNA that causes cancer to build up in our bodies. So a healthy diet is certainly beneficial, but the key answer to your question is that the real damage is done by smoking.