Pre-emptive strike on cancer hope (was Re: Maryanne Kehoe's StupidityWas Not An Accidental Overdose

http://news.bbc.co.uk/2/hi/health/7235565.stm

Last Updated: Monday, 11 February 2008, 00:26 GMT

Pre-emptive strike on cancer hope

Many tumours become resistant to treatment
Scientists have launched a pre-emptive attack on the development of resistance
to cancer treatments.

They have discovered a genetic mechanism by which breast and ovarian cancer
caused by a faulty BRAC2 gene could become resistant to treatment.

It is hoped the findings will both help doctors identify which patients might
benefit most from treatment, and stop drugs from losing their effectiveness.

The study, by the Institute of Cancer Research, is in the journal Nature.

In 2004, over a quarter of a million people were diagnosed with cancer in the
UK, and one in four deaths in the UK are caused by the disease.


By understanding this process we can alter patient treatment to counter the
problem of resistance
Professor Alan Ashworth, study leader

Although diagnosis and treatment is improving, many tumours become resistant
to treatment.

The faulty BRAC2 gene renders cells unable to repair damaged DNA, which can
lead to them becoming cancerous.

Drugs, such as PARP inhibitors and the platinum-based chemotherapy drug,
carboplatin, have been shown to be particularly effective against BRAC2
tumours in early laboratory trials.

They work by causing yet more DNA damage, tipping the cancer cells over the
edge and killing them off.

More advanced trials of the drugs are currently underway in patients with
BRAC2 breast and ovarian cancer - but there are concerns that some tumours
would develop resistance.

The latest phase of the research on tumour cells in the laboratory showed that
after exposure to the drugs, some cells are able to mutate back to the normal
BRAC2 gene, allowing them to overcome DNA damage.

Unfortunately this does not neutralise the tumour - but potentially might
neutralise the impact of the drugs.

The researchers found the same effect in tumour tissue taken from women with
ovarian cancer.

Darwinism

Professor Alan Ashworth, director of the Breakthrough Breast Cancer Research
Centre, said it was a clear example of Charles Darwin's natural selection
theory - cancer cells are able to survive by changing the way treatments
affect them.

"Drug resistance is a problem common to all types of cancer, yet this
important process is poorly understood.

"Our work has shown how this occurs in some women with cancer. In the future
we hope to be able to use this information to predict whether cancer patients
will benefit from particular treatments."

"By understanding this process, we can alter patient treatment to counter the
problem of resistance."

Professor Herbie Newell, Cancer Research UK's executive director of
translational research, said: "This research deepens our understanding of why
some breast cancer patients with a faulty BRCA2 gene may stop responding to
treatment.

"This type of research is becoming increasingly important as we seek to tailor
cancer therapies to individual patients."