An international team has completed the most comprehensive study of whole cancer genomes to date, significantly improving our fundamental understanding of cancer and signposting new directions for its diagnosis and treatment.

Published in Nature, more than 700 researchers have analysed more than 2600 samples from 38 cancer types ranging from common cancers like colorectal and breast cancers, to rare cancer types including pancreatic and brain cancers.

This analysis has enabled researchers to create the first complete atlas of genomes to compare the cancers and find the common mutations between them.

The atlas has been created by an effort known as PCAWG – the Pan Cancer Analysis of Whole Genomes or the Pan-Cancer Project – which has been a collaborative effort of groups from the International Cancer Genome Consortium who agreed to put thousands of sets of patient genome data together and reanalyse these samples using cloud computing.

University of Melbourne Professor Sean Grimmond, who holds the Bertalli Chair in Cancer Medicine, led the Australian efforts which contributed approximately 10 per cent of primary samples from a broad range of tumours including pancreatic, melanoma, neuroendocrine, and ovarian cancer.

Researchers found on average any given tumour has four to five key mutations – changes to the genetic blueprint – that are responsible for driving that disease. Those mutations can vary a great deal for each cancer type.

Previously researchers were aware of one or two drivers. Researchers say understanding that number and realising the complexity in each patient is an important step in working out where else to look when diagnosing cancer patients.

Professor Grimmond said this atlas provides a solid foundation to understand which genes and which pathways may be damaged in each cancer type.

“This research will help identify what types of genetic test are needed for each cancer type – filling in potential existing gaps that we did not even know were there,” Professor Grimmond said.

“It demonstrates better than ever before how similar damage can cause cancer in different tissues – implications mean that for example a breast cancer drug could be effectively used to treat an oesophageal cancer.”

The atlas also provides insight for challenging cancers where the tissue of origin is not known by identifying patterns of damage across various cancer types.

“If we don’t understand where a cancer comes from, we can’t even rely on traditional clinical approaches to treatment,” Professor Grimmond said.

Having a harmonised dataset enables international researchers to learn from one cancer treatment and applies those findings to another using a cloud computing portal.

Researchers say further research with much larger datasets are required to enable precision medicine to truly become a reality.

Dr Peter Campbell, member of the Pan-Cancer Project steering committee and Head of Cancer, Ageing and Somatic Mutation at the Wellcome Sanger Institute in the UK said: “This work is helping to answer a long-standing medical difficulty, why two patients with what appear to be the same cancer can have very different outcomes to the same drug treatment. We show that the reasons for these different behaviours are written in the DNA. The genome of each patient’s cancer is unique, but there are a finite set of recurring patterns, so with large enough studies we can identify all these patterns to optimize diagnosis and treatment.”

Dr Tom Hudson, Chief Scientific Officer at AbbVie and a founder of the International Cancer Genome Consortium said: “The completion of this project represents the culmination of more than a decade of ground-breaking work in studying the cancer genome. When we launched ICGC in 2007, an initiative of this magnitude was unprecedented. I am thrilled that the scientific community has come together to produce this comprehensive study, which enhances our understanding of cancer and fosters the development of new medicines for cancer patients.”

The Australian research groups involved include the University of Melbourne, Peter MacCallum Cancer Centre, QIMR Berghofer, Garvin Institute, University of Queensland, and Melanoma Institute of Australia.