NEW ORLEANS, Mar 28 (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." |
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