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Hans Clevers: "Every day new research is showing us that many types of cancers are fed by tumour stem cells"



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150 leading experts on normal and cancer stem cells gather in Barcelona to discuss their latest breakthroughs in this area and outline strategies for the future.

The biggest challenge in designing new cancer therapies lies in successfully identifying and targeting tumour stem cells, which are responsible for the regrowth of the tumour.

The Barcelona BioMed Conference on “Normal and Tumour Stem Cells”, aims to analyze the function of stem cells in cancer. The conference, which begins today and runs until November 14 at the Institut d'Estudis Catalans, is co-organized by colon cancer research experts Eduard Batlle (IRB Barcelona) and Hans Clevers (Hubrecht Institute, the Netherlands), with the support of the BBVA Foundation. During the three-day event, 21 world experts in the field will meet with a further 130 participants to share their latest research findings on tumour stem cells.

“In 2007 we held the first Barcelona BioMed Conference on this topic. At the time there was only very preliminary data on the relationship between stem cells and cancer. Five years on, many convincing data have emerged to indicate that the majority of tumours are indeed fed by tumour stem cells,” explains Hans Clevers, the scientist who first identified stem cells in the intestine and who today is one of the world leaders in research on normal stem cells and their potential for regenerative therapy.

A number of important studies have demonstrated that at the heart of cancers of the breast, colon, skin, brain, lung and leukemias lie a small group of malignant cells that have retained the properties of the stem cell that gave rise to the cancers in the first place. It is these cells that allow the tumour to grow and can regenerate it. The efforts of many research groups worldwide now focusses on unraveling this process, identifying the specific genes that allow it to occur, and finding ways to detect and eliminate these malignant stem cells.

Stem cells and the origin of tumours

One of the principal characteristics of stem cells is that they are able to copy themselves indefinitely, giving rise to one stem cell and one specialized cell. This capacity for unlimited replication ensures the constant renewal of healthy tissues, which is fundamental for survival and is the basis of regenerative medicine. When the stem cells undergo cancerous mutations or when normal tumour cells acquire stem cell properties, however, this can lead to the formation of tumours.

“This conference gives us a valuable opportunity to learn about the latest work on the two types of stem cells, normal and tumour, in different tissues. What we have been observing over recent years is that the tumour mimcs the hierarchies that exist in normal tissues. In order to understand the tumour, we need to understand the healthy tissue. Most of the scientists invited to the conference are working on both aspects,” explains Batlle. The list of speakers includes pioneers in the field, such as Irving L. Weissman, director of the Institute for Stem Cell Biology & Regenerative Medicine in Stanford, California. Weissman, known as the “father of haematopoiesis”, first identified stem cells in the blood and determined how they give rise to the different types of blood cells, making major contributions to our understanding of leukemias and other ‘liquid’ tumours.

Stem cells and metastasis

In addition to being at the root of the tumour and allowing it to grow, stem cells may also cause metastasis. In order for metastasis to occur, cells from the original tumour must escape into the blood stream and invade new organs to seed new tumours there. “Only cells with stem cell properties are able to make this happen, since they are the only type of cell that can generate all the cell types of the tumor,” explains Batlle. But in order to cause metastasis, these cells also need to be able to do other things. “We have discovered that in the case of colon cancer, stem cells must be able to trick the healthy tissue of the organ they have invaded into helping them survive in this hostile environment.” Batlle’s study, to be published tomorrow in Cancer Cell, will be presented during the conference. This is the first piece of work to reveal a key role for the tumour microenvironment in fostering the process of metastasis, a discovery which will open doors to similar findings in other types of tumours.

Normal stem cells vs. tumour stem cells

One of the keys in the fight against cancer is the ability to identify tumour stem cells and differentiate them from healthy stem cells. The conference co-organizers maintain that “this is still a central question. We don’t yet know enough about normal stem cells, and technical issues make things difficult. We are making rapid progress, however, and in the next few years we expect to be able to make great strides both in figuring out the similarities and differences in the two types of cells, and in coming up with new strategies to fight the growth and spread of tumours.”


EDUARD BATLLE – Group Leader of the Colorectal Cancer Laboratory and Coordinator of the Oncology Programme at IRB Barcelona. ICREA Research Professor (Instituto Catalán para la Investigación y Estudios Avanzados).

Dr. Batlle’s research over the past decade has focused on the characterization of the mechanisms that cause the initiation, progression and metastasis of colon cancer. He has published studies in several high-impact journals such as Cell, Nature, Nature Genetics and Cancer Cell. His achievements include the discovery of the transcription factor Snail in tumour cells and the elucidation of the function of EphB membrane receptors in colorrectal cancer. During the Barcelona BioMed Conference, Dr. Batlle will present the results of a study to be published in Cancer Cell on a process indispensable for colon cancer metastasis.

Among his recognitions, Batlle has received the Banc Sabadell Prize for Biomedical Research (2010) and the “Debiopharm Life Sciences Award for Outstanding Research in Oncology” given by the Ecole Polytechnique Fédérale de Lausanne in Switzerland (2006). He is the recipient of an ERC Starting Grant awarded by the European Research Council in 2007.

HANS CLEVERS – Group leader at the Hubrecht Institute (director 2002-2012 ) and President of the Royal Netherlands Academy of Arts and Sciences. Dr. Clevers was the first scientist to identify intestinal stem cells and remains one of the leading researchers in this field. His discoveries have had significant impact in cancer as well as in regenerative therapy with stem cells and in vitro organ culture. Clevers’ work in developmental biology and cancer led him to discover the beta-catenin/Tcf4 transcriptional complex, which causes the majority of colorrectal cancer.

Hans Clevers has received numerous awards, including the Dutch Spinoza Award (2001), the Swiss Louis Jeantet Prize (2004), the Katharine Berkan Judd Award from the Memorial Sloan-Kettering Cancer Center in New York (2005), and the Israeli Rabbi Shai Shacknai Memorial Prize (2006).

More information about the Barcelona BioMed Conference


The Barcelona BioMed Conferences are an initiative of the Institute for Research in Biomedicine (IRB Barcelona) and the BBVA Foundation, where leading researchers meet to present and discuss breakthroughs in several fields of the biomedical sciences. The conferences aim to provide a highly-focussed think-tank atmosphere for a select group of participants. The series also provides a unique opportunity to highlight the scientific research of excellence being conducted in centres in Catalonia and in Spain to the international community.

“Normal and Tumour Stem Cells” is the 19th gathering in this series, which was started in the Autumn of 2006. Upcoming events in the series include “Bayesian Methods in Biostatistics and Bioinformatics” (December 2012) and “The Microtubule Cytoskeleton in Development and Disease” (March 2013).

About IRB Barcelona

The Institute for Research in Biomedicine (IRB Barcelona) pursues a society free of disease. To this end, it conducts multidisciplinary research of excellence to offer pioneering solutions to unresolved medical needs in cancer and other diseases related to ageing. It establishes technology transfer agreements with the pharmaceutical industry and major hospitals to bring research results closer to society and organises a range of science outreach activities to engage the public in an open dialogue. IRB Barcelona is an international centre that hosts 400 employees and more than 30 nationalities. Recognised as a Severo Ochoa Centre of Excellence since 2011, IRB Barcelona is a CERCA centre and member of the Barcelona Institute of Science and Technology (BIST).