Spanish scientists sequence the genome for chronic lymphocytic leukemia

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BlankSpanish scientists sequence the genome for chronic lymphocytic leukemia

Using state-of-the-art technology, they seek to unraveled the genome of patients

with chronic lymphocytic leukemia and give new key insights into the disease.

The study, which is a scientific milestone in this country, identifies four

genes whose mutation causes this kind of leukemia.

A team of Spanish scientists, among these Modesto Orozco, and p L. Gelpí,

both with the Joint Programme on Computational Biology between IRB Barcelona and

the Barcelona Supercomputing Center (BSC), has sequenced the complete genomes of

healthy and tumor cells from patients with chronic lymphocytic leukemia. This

study concludes that these tumors present about a thousand genome mutations and

that the mutations in four human genes are closely associated with the

development of this kind of leukemia. Published today in the journal Nature,

this study has involved more than 60 researchers from the “Consorcio Español del

Genoma de la Leucemia Linfática Crónica” (CLL Genome) and has implied an

extraordinary human and technical effort. “The data stored at the BSC alone

account for 20 terabytes, the equivalent to more than 200 PC hard disks ”,

explains Orozco.

With more than a thousand diagnoses each year in Spain, chronic lymphocyctic

leucemia is the most frequent leukemia in the developed world. Advances in the

molecular biology of cancer during recent decades have established that this

disease is caused by accumulated gene damage, which leads to uncontrolled

proliferation of B lymphocytes. However, until now the mutations that cause this

runaway cell division were unknown.

In this study the researchers have applied the most advanced technology to

sequence the 3,000 million nucleotides of the complete genome of tumor cells of

four patients and have compared it with the genome sequence of healthy cells

from the same individuals. “This approach has allowed us to confirm that each

tumor has undergone about a thousand mutations in its genome”, explains Dr.

López-Otín, one of the project coordinators. “Later analyses of the mutated

genes in a group of 300 patients allowed us to identify four genes whose

mutations cause this kind of leukemia”.

The breakthroughs of this study, which have come about from the exhaustive

analysis of the first four genomes of patients with chronic lymphocytic

leukemia, have led to the discovery of new mechanisms involved in the

development of this disease. This study confirms the usefulness of mass

sequencing to determine the genetic causes of cancer.

At present, 38 projects are studying 17,000 tumor genomes. In the coming years,

the CLL Genome aims to widen the research to cover the sequencing and analysis

of 500 tumor genomes of 50 types of cancer (25,000 tumor genomes).

The institutions participating in this study are as follows: the Hospital Clínic

de Barcelona; the Instituto Universitario de Oncología de la Universidad de

Oviedo; the Universidad de Barcelona; the Instituto de Investigaciones

Biomèdicas August Pi i Sunyer; the Centro de Regulación Genómica de Barcelona;

the Fundación Instituto de Investigación Biomédica de Bellvitge-Instituto

Catalán de Oncología; the Hospital Universitario and Centro de Investigación del

Cáncer de Salamanca; the Centro Nacional de Investigaciones Oncológicas; the

Universidad de Deusto; the Universidad de Santiago de Compostela; the Barcelona

Supercomputing Center–the National Center for Supercomputing; the Centro

Nacional de Análisis Genómico; and the IRB Barcelona. The study has also

received support from the Wellcome Trust Sanger Institute in Hinxton, United

Kingdom.

Reference article:

Whole-Genome Sequencing Identifies Recurrent Mutations in Chronic Lymphocytic

Leukaemia.

Nature (2011) [doi:10.1038/nature10113]