New research on bowel cancer has shown that every tumour is different, and that every cell within the tumour is also genetically unique. In the first study of its kind, researchers from the Wellcome Sanger Institute, UK and Hubrecht Institute (KNAW) in Utrecht, The Netherlands, used the latest single cell and organoid technologies to understand the mutational processes of the disease.
Reported in Nature, the study will help researchers understand mutational processes, and may allow them to target cancer-specific processes for prevention or treatment.
The team worked on tissue from three patients with colorectal cancer, taking normal bowel stem cells and cells from four different areas of the tumours. They then grew these into organoids - 3D 'mini-guts' - in the laboratory to amplify the single cells so they could be studied.
Colorectal cancer is the third most common type of cancer worldwide making up about 10 per cent of all cancer cases, in the UK alone, over 41 thousand people are diagnosed with the disease every year*.
It was known that colorectal tumours contain subclones that react differently to treatment; however, until now it has not been possible to study single cells from tumours and normal tissue to get an accurate picture.
Prof Hans Clevers, from Hubrecht Institute in the Netherlands, joint corresponding author on the paper, said: "Organoids had not been used to study single cancer cells before. Nobuo Sasaki in my lab isolated multiple single cells from the tumors and grew them up as organoids. This enabled us to study each cell without the errors that standard single cell methods bring. For the first time ever, we could make a really comprehensive comparison of individual normal and tumour cells from the exact same type of tissue, taken at the same time, from the same person, and see how the cancer had developed."
The researchers discovered that the tumour cells had many more mutations than normal cells, and that not only was each bowel cancer genetically different, but each cell they had studied within that cancer was different.
Dr Sophie Roerink, joint first author from the Wellcome Sanger Institute, said: "We found mutational processes in these cancer cells that are just not seen in normal cells, leading to a huge increase in mutation rate for tumours compared with normal cells. This then leads to remarkable genetic diversity within the tumours. We knew before that cancers contained subclones, but this is the first time that anyone has shown that each cell in a tumour is different."
The study discovered that the mutational processes in cancer cells are very different from those in healthy cells and that the increase in mutation rate seems to be a general feature of these colon cancers. Their study also suggests that the mutation rate starts to change many years before the cancer is diagnosed. This time window could provide diagnostic clues in the future if it were possible to identify the rise in mutation rate early in a cell.
Prof Sir Mike Stratton, joint corresponding author on the paper from the Wellcome Sanger Institute, said: "This study gives us fundamental knowledge on the way cancers arise. By studying the patterns of mutations from individual healthy and tumour cells, we can learn what mutational processes have occurred, and then look to see what has caused them. Extending our knowledge on the origin of these processes could help us discover new risk factors to reduce the incidence of cancer, and could also put us in a better position to create drugs to target cancer-specific mutational processes directly."
Notes to editors:
Funding: This work was supported by funding from the Wellcome trust (098051), Stichting Vrienden van het Hubrecht and KWF (SU2C-AACR-DT1213 and HUBR KWF 2014-6917).
About the Hubrecht Institute
The Hubrecht Institute is a research institute focused on developmental and stem cell biology. It encompasses 20 research groups that perform fundamental and multidisciplinary research, both in healthy systems and disease models. The Hubrecht Institute is a research institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), situated on the Utrecht Science Park 'De Uithof'. Since 2008, the institute is affiliated with the University Medical Center Utrecht, advancing the translation of research to the clinic. The Hubrecht Institute has a partnership with the European Molecular Biology Laboratory (EMBL). For more information, visit http://www.hubrecht.eu.
About the Royal Netherlands Academy of Arts and Sciences (KNAW)
The Royal Netherlands Academy of Arts and Sciences is the forum, conscience, and voice of the arts and sciences in the Netherlands. It promotes quality in science and scholarship and strives to ensure that Dutch scholars and scientists contribute to cultural, social and economic progress. As a research organisation, the Academy is responsible for a group of fifteen outstanding national research institutes.
Oncode Institute is an independent institute whose goal is to translate fundamental insights about cancer to improved and more affordable care for patients as efficiently as possible. A team of renowned cancer researchers working in The Netherlands has joined forces within a mission-driven institute focusing on three pillars: excellent research, intensive collaboration and powerful valorization. The Dutch Cancer Foundation invests, together with the Dutch ministry of Economic Affairs & Climate Policy, the ministry of Education Culture & Science, the ministry of Health, Welfare & Sport, Health~Holland, NWO and ZonMw, a total of €120 million in Oncode Institute until 2022. http://www.oncode.nl/
The Wellcome Sanger Institute
The Wellcome Sanger Institute is one of the world's leading genome centres. Through its ability to conduct research at scale, it is able to engage in bold and long-term exploratory projects that are designed to influence and empower medical science globally. Institute research findings, generated through its own research programmes and through its leading role in international consortia, are being used to develop new diagnostics and treatments for human disease. To celebrate its 25th year in 2018, the Institute is sequencing 25 new genomes of species in the UK. Find out more at http://www.sanger.ac.uk or follow @sangerinstitute
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