Drug
Absorption Gene
Differs in Some Ethnicities
NEW ORLEANS
(Reuters Health) - A gene mutation that influences how the body
absorbs HIV medications and chemotherapy drugs is more common
in Europeans and Asians than among those of African heritage,
an international group of researchers has found.
This finding
may one day help doctors decide which therapies work best for
some patients, Dr. Howard L. McLeod of Washington University School
of Medicine in St. Louis, Missouri, reported Sunday at the American
Association for Cancer Research's annual meeting held in New Orleans,
Louisiana.
P-glycoprotein
(PGP), also known as the multidrug-resistance protein, pumps certain
cancer drugs out of cancer cells, rendering them ineffective.
The researchers looked at a variation in the gene that produces
PGP. This mutation reduces PGP function, making it less able to
force drugs out of cells.
McLeod and
colleagues from the University of Aberdeen, the University of
Ghana Medical School and the Riyadh Armed Forces Hospital in Saudi
Arabia, analyzed the genetic makeup of 1,280 people from 10 ethnic
groups.
People who
have two versions of the mutated gene--one inherited from each
parent--have more than four times less PGP than those with two
normal versions of the gene. People may also have one normal gene
and one mutated one.
Among individuals
from Ghana, Kenya, the Sudan, as well as African Americans, frequency
of the normal gene ranged from 73% to 84%. In contrast, the frequency
was 34% to 59% among British whites, Portuguese, Southwest Asian,
Chinese, Filipino and Saudi populations.
Because PGP
affects the effectiveness of cancer drugs and also certain HIV
medications, the high frequency of the normal gene among individuals
of African origin may have relevance to how these individuals
are cared for, McLeod told the audience at a press briefing.
The next step
in his research, McLeod said in a statement, will be to see if
people with the mutated version of the gene--who likely have less
PGP--respond better to chemotherapy than those with a non-mutated,
normal version.
``People ask,
when will genomic information be of use to individual patients?
This presentation shows that today is that day,'' Dr. Jeffrey
Trent, of the National Human Genome Research Institute in Bethesda,
Maryland, said in summary comments. ``Now we can tailor treatment,
dosage, drug combinations.''
Trent told
Reuters Health, ``There's no doubt we're moving to an area where
data rules. The ability to access tools that allow us to link
information is going to be the critical common denominator internationally.''
He added,
``The problem is linking the data, merging information between
centers while being sensitive to current laws and guidelines that
prohibit us from moving data without consent. These are the areas
that are going to be particularly challenging to us.''
Reference
Source 89
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