MEDICUS MARCH 2016

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PROFESSOR ROSSA CHIU , a Fellow of the Royal College of Pathologists of Australasia (RCPA), has said that her team’s latest developments in human plasma cancer DNA analysis are pushing new boundaries by identifying the organs where cancer is located via a blood test. This approach, termed plasma DNA tissue mapping, is akin to performing a CT scan using blood samples. Professor Chiu and her colleagues at the Chinese University of Hong Kong (CUHK) have developed new methods to diagnose cancer, conduct prenatal diagnosis, and assess patients who suffer from an auto-immune condition called Systemic Lupus Erythematosus. Professor Chiu predicts that it could be just a few years away from this latest technology being implemented in regular medical practice. “We have developed a brand new technology, which takes plasma cancer DNA analysis, also known as liquid biopsy, to the next level. “Now, the technology is not only able to detect abnormal DNA caused by cancer, it also allows us to scan a blood sample in order to locate where (which organ) the abnormal DNA is coming from. For instance, we might be able to identify that 10 per cent of the DNA is from the liver, or in expectant mothers, 20 per cent is coming from the placenta. “In the past, we have tried to find a marker for liver cancer, however every cancer is very different and no single marker is particularly useful for a specific type of cancer. “With our latest technology, we have improved the blood-based test so much that we can now look at the profiles in the blood sample and then map out which tissues are making regular and abnormal amounts of contribution. Generally it takes approximately one week to analyse.” ■ BLOOD TEST THAT DETECTS CANCER’S LOCATION BEING DEVELOPED FOR CLINICAL USE

GROUND-BREAKING DISCOVERY IN VERTEBRATE DEVELOPMENT PROCESS

RESEARCHERS FROM THE Harry Perkins Institute of Medical Research have uncovered molecular instructions that provide important information required for the

formation of embryonic body structures, such as limbs or the nervous system, by comparing these processes in fish, frogs and mice.

Prof Ryan Lister and Dr Ozren Bogdanovic.

Professor Ryan Lister and Dr Ozren Bogdanovic from the Perkins Epigenetics and Genomics Laboratory led the study, which has been published in in the prestigious journal Nature Genetics . Their work is focused on the epigenome, an extra layer of information present in cells that is made up of millions of miniscule chemical tags attached to the DNA, that can switch genes on or off and instruct a cell on how to develop into different tissue, such as skin or heart. Laboratory Head Professor Lister said there was a phase during embryonic development when very different animal groups look remarkably similar. During this phase, these pre-programmed epigenetic signposts switch genes on or off to trigger the correct development of early embryonic structures. The researchers use powerful genome analysis technologies to precisely map the location of these chemical signposts, in order to better understand the epigenetic process of development, which could be used in the future to show how these processes may go awry and cause disease or disability. Dr Bogdanovic, the first author of the study, said the researchers were comparing the way these epigenetic signposts changed throughout embryo development in different species in order to form a blueprint for normal development. “By looking at early stage embryos of different species, we were able to find the existence of multiple epigenetic switches that appear to be critical for limb formation or brain development,” Dr Bogdanovic said. “The switches change similarly in all these different organisms, even though they’re separated by hundreds of millions of years of evolution.” ■

Pushing boundaries: Plasma DNA tissue mapping is like performing a CT scan using blood samples.

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