[icon-discuss] Canadian researchers make breast cancer breakthrough

From: Linda Gehres <ljgehres@xxxxxxxxxxx>
To: Linda Gehres <ljgehres@xxxxxxxxxxx>
Date: Thu, 08 Oct 2009 09:56:14 -0700
If true, what a modern-day miracle this would represent!!

Linda G.

Canadian researchers make breast cancer breakthrough

Scientists decode tumour DNA, identify mutations that cause disease to
Spread 

Carly Weeks
Globe and Mail, Oct. 07, 2009

The possibility of using a patient's genetic information to create
personalized therapies to battle cancer is one step closer to reality after
Canadian scientists decoded, for the first time, the entire genome of a
patient's metastatic breast cancer.

It's a landmark achievement that is helping to rewrite old notions about the
way cancer develops and provides new insights into which drugs could benefit
patients the most.

"I'm excited by the possibilities," said Samuel Aparicio, the head of the
department of breast and molecular oncology at the B.C. Cancer Agency and
one of the lead scientists involved with the discovery. "In fact, I never
thought I would see in my professional
lifetime that it would become possible to routinely sequence genomes in the
way that we're now doing."

Genomes contain all of the biological information of a living organism, and
that information is housed in DNA. There are about three billion "letters"
or building blocks in the human genome. When cells divide, all three billion
building blocks must be copied. But mistakes in the copying process can
sometimes occur, and those
mutations can, in some cases, cause cells to grow in an uncontrolled way -
which is how cancer develops.

In decoding the metastatic breast-cancer genome, which contains all of the
genetic information of a patient's cancer, scientists were able to identify
all of the mutations in the tumour, a feat that has never before been
accomplished. 

"We've been dreaming about the possibility to capture complete genome
Information from cancers in a routine way for decades. The moment has
arrived."

- Samuel Aparicio, a lead scientist in the research
But the breakthrough didn't stop there. Once all of the tumour mutations of
the developed cancer were identified - a total of 32 were found - scientists
had the information to look back and see which of those mutations were
present in the patient's original,
primary tumour. They discovered that only 11 of the 32 mutations were
present in the original tumour, with only five of those present in all of
the original cancer cells, meaning that even in the early stages, cancer
cells aren't uniform. That's significant because it proves even from the
outset, cancer cells contain different mutations which change
over time.

While scientists have theorized that cancer cells can differ, even in a
single individual, until now it has never been possible to sequence the
cancer genome and determine what mutations are present and how they evolve.

"I think we're getting used to the idea an individual patient's cancer is
itself multiple individual cancers that may behave differently," said Dr.
Aparicio, who holds the Canada research chair in molecular oncology and is
the Nan and Lorraine Robertson chair of breast-cancer research at the
University of British Columbia.

The findings, discovered by a research team led by Dr. Aparicio and Marco
Marra, director of the Michael Smith Genome Sciences Centre at the B.C.
Cancer Agency, are published Thursday in the journal Nature.
A major portion of the money used to fund the research came from the B.C.
Cancer Foundation's Weekend to End Breast Cancer walk, as well as donations
raised across the province during the annual breast-cancer walk over the
past six years. Funding also came from other groups, including the Canadian
Breast Cancer Foundation.

The next major challenge will be interpreting the mutations to understand
their significance and determine which mutations are vulnerable to which
treatments.
Eventually, scientists hope to decode cancer genomes from a large number of
patients to determine if there are any patterns in the genetic mutations or
the overall significance
of various mutations. Dr. Aparicio said their work could help usher in a new
era in which scientists will be able to decode cancer genomes in all
patients to help create therapies targeted to the mutations present in their
tumours.

This also means patients may have to undergo numerous tests as their disease
progresses to account for the fact that an individual's cancer goes though
multiple changes over time.
A growing number of researchers have put stock in recent years into the idea
that genome sequencing holds the key to understanding cancer development and
creating targeted therapies. Yet, the exorbitant cost and complex process of
genome sequencing has always put those lofty goals out of reach.

But now, a series of technological advancements has brought down the cost
dramatically, which means the "possibility of obtaining genome sequence from
every patient's tumour is coming closer," Dr. Aparicio said.

The scientists involved in this advance used next-generation DNA sequencing
technology to decode the cancer genome, new technology that is lowering
costs and helping to fuel genome-related research and discoveries around the
world.

"We've been dreaming about the possibility to capture complete genome
Information from cancers in a routine way for decades," Dr. Aparicio said.
"The moment has arrived."
[icon-discuss] Canadian researchers make breast cancer breakthrough

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