Australian discovery leads to new test for aggressive cancers

Scientific research by the Children’s Medical Research Institute (CMRI), Sydney, has enabled the development of a test for approximately 15% of all cancers, including some of the most aggressive and potentially lethal.

The test or assay will speed up the search for drugs to treat these cancers because it offers a rapid method for screening compounds for potential for development in anti-cancer drugs.

For some aggressive brain tumours, and maybe some other cancers, this test will provide more accurate life expectancy information for patients where doctors now have very little clarity.

The assay can also be used as a blood test for some cancers.  Medical checkups in future might include a blood test to detect these cancers, and the blood test might also be used to monitor the effectiveness of cancer treatments.

This research – which provides insights into the mechanics of about 15% of all cancers – is published in the prestigious international scientific journal Nature Biotechnology on Monday 23 November.

Almost all cancers use one of two mechanisms to multiply indefinitely and become ‘immortal’.  About 15% of cancers, including some aggressive brain and bone cancers, and some breast and lung cancers, use the ‘alternative lengthening of telomeres’ (ALT) mechanism, measured by this new test from Dr Jeremy Henson and the team at CMRI.  The other 85% use the enzyme telomerase – the subject of the 2009 Nobel Prize in Medicine for Australian-born Elizabeth Blackburn and her US colleagues.

Both ALT and telomerase have low or undetectable activity in most normal cells, so there is enormous potential for developing drugs that target these mechanisms to treat cancer – hopefully with far fewer side-effects than today’s chemotherapies.

Prof Roger Reddel, Director of Children's Medical Research Institute, heads its Cancer Research Unit which is at the international forefront of research into both telomerase and ALT.  His team discovered ALT in 1995, and in 2007 were the first to discover the molecular composition of human telomerase.  Dr Henson has been a member of the team since 2001 and has been working on tests for ALT throughout that time.

Dr Henson’s work on the ALT assay was made possible by generous support from the Cancer Council NSW and donors to Jeans for Genes and CMRI.

‘This groundbreaking test will help researchers improve outcomes for some of the most life-threatening forms of cancer.  It could also hugely benefit patients by paving the way for new treatments that have fewer side-effects than those now available,’ Dr Andrew Penman, CEO of Cancer Council NSW, said.  ‘The Cancer Council is delighted to support the Children’s Medical Research Institute team who made this exciting discovery.’

The Children’s Medical Research Institute studies genes and their role in healthy development and disease.  Childhood diseases including epilepsy, cleft palate and cancer still affect one child in 20.  Find out about CMRI at www.cmri.org.au.  

This not-for-profit organisation receives funding through competitive grants and events including Jeans for Genes Day (6 August, 2010).

MEDIA - to arrange interviews with Dr Jeremy Henson and Professor Roger Reddel - please call Feehan Communications on 02 9267 2711 or email tina@feehanpr.com.  

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Further background

Until now, efforts to understand the ALT mechanism and work towards ALT-blocking treatments have been stymied by lack of an accurate, rapid test for measuring ALT activity.  Previously, the only reliable method for determining the level of ALT activity in a tumour took about three months per experiment.

Dr Henson and colleagues made the surprising discovery that there are circles of partially single-stranded DNA in ALT cells and, even more surprisingly, that the number of these circles correlates closely with the amount of ALT activity.  The circles disappear within 24 hours when ALT is inhibited, so they provide a very sensitive and rapid indicator of ALT activity.  Dr Henson also found that ALT-positive osteosarcomas (bone cancers) shed this circular DNA into the bloodstream.

Also working as a practising locum doctor once a month, Dr Henson sees first-hand the distress caused by these devastating diagnoses.  It is this knowledge and his insatiable curiosity that have been the driving force for his success with this new ALT assay.

Dr Henson has comprehensively verified the specificity and sensitivity of the assay in the laboratory using CMRI’s extensive collection of ALT-positive cell lines.  He has designed the assay to enable its use in hospital histopathology laboratories.

MEDIA - to arrange interviews with Dr Jeremy Henson and Professor Roger Reddel - please call Feehan Communications on 02 9267 2711 or email tina@feehanpr.com.

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