Surveys have shown one third of Kiwis think science is too specialised to understand. In this series, scientists who tackle mind-bogglingly complex problems each day make it simple for us. Today, we talk to Otago University cancer researcher Dr Parry Guilford

How would you describe what you do to a peer at a conference? And then how would you talk to a stranger at a barbecue?

Conference: We are taking a synthetic lethal approach to identify druggable vulnerabilities in cells with CDH1 mutations.

Barbecue: Some cancers contain mutations in a gene called CDH1.


Although these mutations make the cancer more invasive, we think this increased aggression must come at a cost, creating vulnerabilities in the cell.

We are trying to identify those vulnerabilities so we can develop drugs which exploit them and kill the cancer cell.

Is that the tomato sauce over there?

What project or projects are you currently working on at the moment and what's involved?

We are working on two main projects.

One aims to establish a new type of cancer blood test into the New Zealand healthcare system.

The test, called circulating tumour DNA, measures DNA that has been spilt from tumours into the bloodstream.

We can recognise that it has come from a tumour by the presence of DNA mutations in known cancer genes.


The plan is to use the test to monitor cancer patients through the course of their treatment to make sure the treatment is working well.

If a cancer is shrinking, the circulating tumour DNA levels will drop; if its growing, the levels will be increasing.

Because it is just a blood test, we will be able to keep a much closer on treatment response than is possible with current technologies - like CT scans which can only be done every eight to 12 weeks.

It will also mean that people won't need to travel to the hospital as much, just sending a blood sample instead.

I think this technology will transform cancer care in New Zealand.

The other main project aims to develop new treatments for families with an inherited cancer syndrome called Hereditary Diffuse Gastric Cancer.

Some members of these families have a 70 per cent chance of developing stomach cancer and also a higher risk of breast cancer.

Currently, those at risk have their stomachs removed to eliminate that risk.

Although this isn't quite as bad as it sounds, we would like to find a better way to look after these families, so we are trying to develop drugs that stop the cancers developing.

We hope that these same drugs will also be useful treatments for the more common, non-inherited, forms of stomach and breast cancer.

What are the trickiest questions facing your field and why is solving them so difficult?

The development of drug resistance.

Not all cells in a tumour are the same, in fact most are subtly different.

This means that there are often a few cells in every tumour that are treatment resistant.

So, when the bulk of the tumour is killed by a drug, these resistant cells remain and then grow back.

What we are effectively seeing is rapid evolution on a very local scale.

To solve this we are going to need to understand what these resistant cells are doing that is different and then develop drug combinations that knock off the main tumour and the resistant cells.

Fortunately, this is all do-able, but it will take time.

Is your sausage burnt?

What do you feel are the most interesting or fascinating aspects of your field?

Cancer is incredibly complex, but there is no magic to it.

It has thrown up a million questions, most of which have been answered at least in part.

What we see is the most remarkable capacity of tissues in the human body to live, not matter what hardship they are put under.

So, in some ways, cancer is the unfortunate side effect of everything that has made complex animals like humans the success they are.

Like jets with a tendency to over-run the runway.

Why do you think the work is important and what could it help us understand?

Although cancer is inevitable, we must continue to research and resist because too many people don't get a fair crack at life in all its various stages.

It's our shared concern - there we all go but for the grace of God or the throw of the dice.