Sequencing of 2,600 tumours unearths cancer's genetic secrets
Unprecedented exploration discovers causes of previously unexplained cancers, locates cancer-causing events and has zeroed in on mechanisms of development.
An international team, which includes Professor Chris Scarlett from the Faculty of Science, has completed the most comprehensive study of whole cancer genomes to date, significantly improving our understanding of cancer and signposting new directions for its diagnosis and treatment.
Featured in the February 6th edition of Nature and its affiliated journals, the findings highlight the decade-long international efforts cataloguing whole genomes from 38 cancers, by the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes Project (PCAWG), known as the Pan-Cancer Project.
The Pan-Cancer Project involves more than 1,300 scientists and clinicians from 37 countries, who analysed more than 2,600 genomes and created a huge resource of primary cancer genomes. This was then the launch-point for 16 working groups studying multiple aspects of cancer’s development, causation, progression and classification.
Professor Scarlett said that while previous studies focused on the 1 per cent of the genome that codes for proteins, the Pan-Cancer Project mapped the remaining 99 per cent of the genome, including key regions that control switching genes on and off.
“Collectively, we explored the genome in considerably greater detail than any research before us,” said Professor Scarlett.
“We have essentially gone from mapping the coasts of continents to their entire interiors. With this comprehensive knowledge, new tools for early detection and more targeted, successful treatments can be developed.”
The findings from the Pan-Cancer Project conclude that:
- The cancer genome is finite and knowable, but enormously complicated. By combining sequencing of the whole cancer genome with a suite of analysis tools, we can characterize every genetic change found in a cancer, all the processes that have generated those mutations, and even the order of key events during a cancer’s life history.
- Researchers are close to cataloguing all of the biological pathways involved in cancer and having a fuller picture of their actions in the genome. At least one causal mutation was found in virtually all of the cancers analysed and the processes that generate mutations were found to be hugely diverse -- from changes in single DNA letters to the reorganization of whole chromosomes. Multiple novel regions of the genome controlling how genes switch on and off were identified as targets of cancer-causing mutations.
- Through a new method of “carbon dating,” Pan-Cancer researchers discovered that it is possible to identify mutations which occurred years, sometimes even decades, before the tumour appears. This opens, theoretically, a window of opportunity for early cancer detection.
- Tumour types can be identified accurately according to the patterns of genetic changes seen throughout the genome, potentially aiding the diagnosis of a patient’s cancer where conventional clinical tests could not identify its type. Knowledge of the exact tumour type could also help tailor treatments.
Pro Vice-Chancellor for the Faculty of Science, Professor Lee Smith, said the results were a testament to the dedication and coordination of the international consortium.
“This is an exciting milestone in cancer research. On behalf of the Faculty of Science, I congratulate Professor Scarlett on his role in such a significant project and look forward to seeing how it fosters real-world benefits for cancer patients going forward.”
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