Stephanie Nardei, Outreach Information Specialist, Southwest
Environmental Health Science Center
determine the color of our eyes and shape of our bodies. Genes
also determine our susceptibility to disease and how we respond
to certain medicines. Genomics is the study of an individual's
gene structure, including how the genes interact with each
other and with our environment. Experts say genomics has the
to revolutionize the practice of medicine. That revolution,
called "personalized medicine," includes the use of genomic information
to advance the diagnosis of disease, as well as the prevention
and treatment of disease.
This is one of the areas Dr. Serrine Lau of the Southwest Environmental
Health Science Center of the Center of Toxicology at the University
of Arizona is presently exploring. “Genetic make-up is unique with everyone”, says Dr. Lau, “This new field of personalized medicine will uncover things about how our individual bodies interact with the environment that we never could have imagined before.” It
is going to be very exciting over the next decade to see what toxicologists
such as Dr. Lau discover about preventive approaches with personalized
example of a preventive approach is when a genetic test predicts which diseases
an individual is likely to develop. For instance, people who have certain
mutations in a particular gene have a high risk of developing
certain types of cancer
or related disease. Dr. Lau says, personalized medicine tries
to answer questions
Why do some people get cancer and others don't?
Why is cancer more aggressive in this person compared to that one?
Why does this drug work for you and not me?
Why does someone need twice the standard dose to be effective?
Why do others need only half of the standard dose?
"The goal of personalized medicine is to get the best medical outcomes by choosing treatments that work well with a person's genomic profile, or with certain characteristics in the person's blood proteins or cell surface proteins,” says Serrine. Pharmacology (the combination of drugs) with genomics is known as pharmacogenomics, the science allowing researchers to predict probability of a drug response based on a person's genetic makeup. "It's about getting the right dose of the right drug to the right patient at the right time," Dr. Lau says.
The usual doses of drugs work well for most people. They are sometimes based on weight, age, and kidney function. But for someone who metabolizes a drug quickly, the typical dose may be ineffective and a higher dose may be needed.
someone who is a slow metabolizer may need a lower dose; the
typical dose could cause toxic levels of the drug to build up
in the blood. When we take medicine, it moves through our body,
gets broken down by drug-metabolizing enzymes, and interacts
with countless proteins. "Genes regulate drug metabolism," Serrine says. "Differences in the sequence of a gene can cause differences in enzyme activity, which is a result of enzymes appearing in various forms in individuals. This is why different people process the same drug differently." Dr. Lau says that for children with leukemia, getting the dose wrong can mean the difference between life and death. "We want to keep harsher treatments away from children whose bodies can't tolerate them or don't need them," she says.
The main benefit
of pharmacogenomics for consumers is the availability of drugs
with a greater chance of benefit for treating illnesses. Consumers
want effective treatment and minimal side effects. They wish
to know they are getting the right drug and the right dose. There
are people who feel like they are always experiencing bad side
effects from drugs, and in many cases, genetics plays a serious
role. If we could find out who the susceptible people are so
they can avoid the risk, we could target a drug more appropriately
for that unique population instead of removing it from the market.
The hope for
the future is through personalized medicine, doctors and patients
will be able to make better informed choices about treatment.
Genetic information could lead them to decide which drug to
use, whether to lower a dose, or whether closer monitoring of
patient for side effects is needed. Personalized medicine is
one of bringing balance to an evolving science in a way that
reaps the benefits, but also doesn't inhibit its growth. The
most common approach to drug treatment now is doctors give
all patients with a given disease the same drug and an average
evaluate how it works, and then make adjustments as needed.
But with life-threatening illnesses such as cancer and heart
and with drugs that can have serious side effects, “getting it right the first time is crucial," Serrine says. Rather than using a trial-and-error approach, we want to be able to “analyze a patient's genetic profile and prescribe the best therapy and dose from the start.”
A major challenge,
Serrine reports, is that there is a general lack of familiarity
with pharmacogenomic data because the science is so new and is
constantly evolving in new ways. "I think it will require a new way of thinking about individualization, and some people will be resistant to change given the challenges of understanding the information," she says.
With that being said, Serrine wants to encourage everyone to not “just sit around and wonder what comes next”, but instead “become informed, get the information you need as a consumer”. Everyone has a responsibility for their own health care needs and welfare. Ask questions of your doctors, do the research and learn all you can to become a better you.
to high school students, Serrine urges everyone to “give environmental health a try. You may find it far more interesting than you thought.” The reason is environmental health is one of those fields that “you do not fully understand until you delve into it.” She knows it is not for everyone, but she advises students to at least take a peek and see what it is all about. If you discover it is not for you, that is alright, but at least, you gave it a chance, Lau advises.
When Serrine’s son was 16 years old, she invited him to spend his high school summer working in the lab to give him an exposure to the field of toxicology. So, her son did indeed spend the summer working in the College of Pharmacy labs.
At the end
of the summer, he apprehensively asked to speak to his mother
saying there was something he needed to discuss with her. Serrine
sat down and listened to what her son had to say. With more fear
in his voice, he told his mother, “This is not for me, Mom. I do not like science or toxicology.” Serrine smiled and told him that is was okay, “At least you gave it a try. You allowed yourself to be exposed to it. That is all I asked.” And that is all she advises students everywhere is to “Just give it a try. Get the exposure. If it is not a right match for you, that is fine, but don’t knock it until you try it.”
As said before,
environmental health and toxicology is one of those fields that
you cannot fully appreciate until you have been exposed to it.
Born and raised in Hong Kong, Serrine Lau always loved science
in high school. “It was my favorite subject when I was in high school and I also liked math,” she says. Initially, Serrine was interested in pursuing medicine, but did not think she had the emotional stamina to treat patients, so she pursued a career in pharmacology, which led to her desire for toxicology. “I have no regrets,” says Dr. Serrine Lau, “If
I had to do it all over again, I would.”
is a project of the Community Outreach and Education
Program of the Southwest Environmental Health Sciences
Center and is funded by: