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醫療新知
破解乳癌21組遺傳密碼
英國科學家成功找到引致乳癌的21組基因遺傳密碼，成為醫學界一大突破。當地劍橋聖格研究院的專家，透過分析病人 基因樣本，發現有關遺傳密碼，並總結出有五大重要過程可致基因出現變異，將乳房的正常細胞變成癌細胞。 乳癌是女性常見的癌症殺手。世界衞生組織最新數據指，全球每年有45萬名女性死於乳癌，佔整體癌症死亡率16％。負責研究的專家表示，今次發現有助醫學界 掌握乳癌的形成及演變，長遠有助研發更多有效治療方法。全球乳癌新症由1980年有64萬宗，增至前年160萬宗，30年間的增幅逾一倍。
Scientists have mapped the complete
genetic codes of 21 breast cancers and created a catalogue of the
mutations that accumulate in breast cells, raising hopes that the
disease may be able to be spotted earlier and treated more effectively
in future.
The research, the first of its kind, untangles the genetic history of how cancer evolves, allowing scientists to identify mutational patterns that fuel the growth of breast tumors, and start to work out the processes behind them.
"These findings have implications for our understanding of how breast cancers develop over the decades before diagnosis in adults and might help to find possible targets for improved diagnosis or therapeutic intervention in the future," said Mike Stratton, who led the research team.
Breast cancer kills more than 450,000 women a year worldwide and is the most common cancer among women, accounting for 16 percent of all cases, according to the World Health Organization (WHO).
A study last year by the Institute for Health Metrics and Evaluation in the United States found that global breast cancer cases have more than doubled in just three decades, from 641,000 cases in 1980 to 1.6 million cases in 2010 - a pace that far exceeds global population growth.
"This is the first time we've been able to delve fully into breast cancer genomes in such a thorough way," said Peter Campbell, head of cancer genetics and genomics at the Wellcome Trust Sanger Institute in Cambridge, where the studies were led.
The work had given scientists "a full panoramic view of the cancer genome" and helped them identify "mutational patterns rather than individual mutations in specific genes", he added.
DNA MUTATIONS
"We've known for many years now that all cancers are due to abnormalities of DNA...that occur in every single cell of the body over the course of a lifetime," said Stratton.
"But although we've known that, it's remarkable how rudimentary our knowledge is about what the processes are that cause these abnormalities, these mutations in our DNA."
Stratton's team sequenced the genomes of the 21 breast cancers and catalogued all the mutations. They found five major processes that cause one letter of code to be changed to another letter. Genetic code comes in four DNA letters, A,C,G and T.
Stratton said one of the most exciting findings was that one of these processes is characterized by small pockets of massively mutated regions of the genome. This sudden "storm" of mutations is often seen in breast cancers, he explained in an audio briefing.
While his team don't fully understand the process behind these storms, they think it may be down to components of the cell whose normal function is to edit, or mutate, DNA.
"What we believe...is that sometimes in normal cells...this stops functioning properly and over-functions. It causes too many mutations and the accumulation of those mutations pushes the cell along the line to become cancer."
The team found that these and other mutations accumulate in breast cells over many years, initially slowly, but picking up greater momentum as genetic damage builds up.
By the time the breast cancers are large enough to be diagnosed, they are made up of a number of genetically related families of cells, with one family dominating the cancer, Stratton explained.
Mark Walport, director of the Wellcome Trust which helped fund the work, said the results showed how scientists are starting to see the landscape of mutations in breast cancer "in something approaching its full complexity".
"As this work continues, we can hope to understand how breast cancer develops and thus how it might be treated more effectively," he said in a statement.
Scientists have created a genetic 'map' of breast cancer
A genetic "map" of breast cancer has been drawn, revealing the varied landscape of the disease in more detail than ever before.
The research is expected to lead to more accurate diagnoses and effective treatments.
Scientists described nine new genes that drive the development of breast cancer, bringing the known total to 40.
Breast cancer was shown to be not so much a single disease as a diverse range of cancer "species". Most individual cancers had different combinations of mutated cancer genes.
The research, conducted by a large international team of British-led experts, involved analysing DNA from 100 tumour samples. Scientists scoured more than 21,000 genes for cancer-causing "driver" mutations that can turn an ordinary cell into one that multiplies uncontrollably.
They also identified nine genes previously not known to be linked to the disease.
Study leader Professor Mike Stratton, director of the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, said: "In 28 cases we found only a single driver, but the maximum number of driver mutations in an individual cancer was six. We found that breast cancer can be caused by more than 70 different combinations of mutations.
"If we consider three breast cancers, each with four driver mutations: they might share none of those driver mutations - so each is a different genetic 'animal'. They are different cancers driven by different genes. We need to classify them as carefully as we can. This study is a step towards that goal."
All cancers carry mutations - changes in the genetic code - that are acquired during a person's lifetime. A subset of these, known as driver mutations, are causally related to the development of cancer. Others, called "passenger" mutations, may be present without directly triggering the disease.
The new research, published in the journal Nature, involved the first comprehensive exploration of breast cancer driver mutations. Scientists hope their findings will ultimately lead to new and better treatments, tailored to the genetic make-up of individual patients.
英國科學家成功找到引致乳癌的21組基因遺傳密碼，成為醫學界一大突破。當地劍橋聖格研究院的專家，透過分析病人 基因樣本，發現有關遺傳密碼，並總結出有五大重要過程可致基因出現變異，將乳房的正常細胞變成癌細胞。 乳癌是女性常見的癌症殺手。世界衞生組織最新數據指，全球每年有45萬名女性死於乳癌，佔整體癌症死亡率16％。負責研究的專家表示，今次發現有助醫學界 掌握乳癌的形成及演變，長遠有助研發更多有效治療方法。全球乳癌新症由1980年有64萬宗，增至前年160萬宗，30年間的增幅逾一倍。
Study unpicks gene changes behind breast cancer
Photo credit: Getty Images | Helen Darling of the San Antonio Silver Stars receives a screening mammogram at Christus Santa Rosa Hospital-Westover Hills at the AT&T Center in San Antonio, Texas. (Aug. 18, 2009)
The research, the first of its kind, untangles the genetic history of how cancer evolves, allowing scientists to identify mutational patterns that fuel the growth of breast tumors, and start to work out the processes behind them.
"These findings have implications for our understanding of how breast cancers develop over the decades before diagnosis in adults and might help to find possible targets for improved diagnosis or therapeutic intervention in the future," said Mike Stratton, who led the research team.
Breast cancer kills more than 450,000 women a year worldwide and is the most common cancer among women, accounting for 16 percent of all cases, according to the World Health Organization (WHO).
A study last year by the Institute for Health Metrics and Evaluation in the United States found that global breast cancer cases have more than doubled in just three decades, from 641,000 cases in 1980 to 1.6 million cases in 2010 - a pace that far exceeds global population growth.
"This is the first time we've been able to delve fully into breast cancer genomes in such a thorough way," said Peter Campbell, head of cancer genetics and genomics at the Wellcome Trust Sanger Institute in Cambridge, where the studies were led.
The work had given scientists "a full panoramic view of the cancer genome" and helped them identify "mutational patterns rather than individual mutations in specific genes", he added.
DNA MUTATIONS
"We've known for many years now that all cancers are due to abnormalities of DNA...that occur in every single cell of the body over the course of a lifetime," said Stratton.
"But although we've known that, it's remarkable how rudimentary our knowledge is about what the processes are that cause these abnormalities, these mutations in our DNA."
Stratton's team sequenced the genomes of the 21 breast cancers and catalogued all the mutations. They found five major processes that cause one letter of code to be changed to another letter. Genetic code comes in four DNA letters, A,C,G and T.
Stratton said one of the most exciting findings was that one of these processes is characterized by small pockets of massively mutated regions of the genome. This sudden "storm" of mutations is often seen in breast cancers, he explained in an audio briefing.
While his team don't fully understand the process behind these storms, they think it may be down to components of the cell whose normal function is to edit, or mutate, DNA.
"What we believe...is that sometimes in normal cells...this stops functioning properly and over-functions. It causes too many mutations and the accumulation of those mutations pushes the cell along the line to become cancer."
The team found that these and other mutations accumulate in breast cells over many years, initially slowly, but picking up greater momentum as genetic damage builds up.
By the time the breast cancers are large enough to be diagnosed, they are made up of a number of genetically related families of cells, with one family dominating the cancer, Stratton explained.
Mark Walport, director of the Wellcome Trust which helped fund the work, said the results showed how scientists are starting to see the landscape of mutations in breast cancer "in something approaching its full complexity".
"As this work continues, we can hope to understand how breast cancer develops and thus how it might be treated more effectively," he said in a statement.
Genetic breast cancer 'map' drawn
A genetic "map" of breast cancer has been drawn, revealing the varied landscape of the disease in more detail than ever before.
The research is expected to lead to more accurate diagnoses and effective treatments.
Scientists described nine new genes that drive the development of breast cancer, bringing the known total to 40.
Breast cancer was shown to be not so much a single disease as a diverse range of cancer "species". Most individual cancers had different combinations of mutated cancer genes.
The research, conducted by a large international team of British-led experts, involved analysing DNA from 100 tumour samples. Scientists scoured more than 21,000 genes for cancer-causing "driver" mutations that can turn an ordinary cell into one that multiplies uncontrollably.
They also identified nine genes previously not known to be linked to the disease.
Study leader Professor Mike Stratton, director of the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, said: "In 28 cases we found only a single driver, but the maximum number of driver mutations in an individual cancer was six. We found that breast cancer can be caused by more than 70 different combinations of mutations.
"If we consider three breast cancers, each with four driver mutations: they might share none of those driver mutations - so each is a different genetic 'animal'. They are different cancers driven by different genes. We need to classify them as carefully as we can. This study is a step towards that goal."
All cancers carry mutations - changes in the genetic code - that are acquired during a person's lifetime. A subset of these, known as driver mutations, are causally related to the development of cancer. Others, called "passenger" mutations, may be present without directly triggering the disease.
The new research, published in the journal Nature, involved the first comprehensive exploration of breast cancer driver mutations. Scientists hope their findings will ultimately lead to new and better treatments, tailored to the genetic make-up of individual patients.
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