Can Genetic Research Yield Cancer Cure?

New treatments already show great promise

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By
HealthDay Reporter

FRIDAY, April 11, 2003 (HealthDayNews) -- They call it the genetics of cancer, and researchers predict that one day it may lead to a cure.

The approach has already hinted at a number of potentially remarkable advances, such as creating individualized -- even painless -- treatments, and finding the shared genetic characteristics between such diseases as lung, colon and breast cancer.

While this may sound like science fiction, research in cancer genetics is already yielding dividends.

The recent development of the highly effective leukemia drug Gleevec is considered a milestone because it targets cancer cells, while leaving healthy tissue intact and causing few side effects, oncologists note.

Gleevec is used to treat chronic myeloid leukemia. However, it has spawned a new class of "targeted-therapy" drugs, and is being tested on other cancers as well, such as pediatric bone cancer.

"For the first time, cancer researchers now have the necessary tools to probe the molecular anatomy of tumor cells in search of cancer-causing proteins," Dr. Richard Klausner, director of the National Cancer Institute, says of Gleevec, which was approved two years ago by the U.S. Food and Drug Administration.

The basic method of developing drugs like Gleevec is fairly simple: isolate the genetic markers of cancer to find the ones that trigger the tumor. Then test various drugs against those trigger genes to see how they react. As a possible side benefit, the data collected through the process may one day illuminate genetic links between cancers.

"It may not be that all cancers can boil down to a certain gene, but it may be that certain sets of cancers, such as skin cancer, have shared characteristics," says Dr. Peter Maslak, chief of the hematology laboratory at the Memorial Sloan-Kettering Cancer Center in New York City.

"There's a tremendous amount of hope that within five or 10 years we're going to understand the genetics of most cancers," adds Dr. Len Lichtenfeld, with the American Cancer Society's science department.

But with April designated as Cancer Control Month, Lichtenfeld emphasizes the best cure for cancer remains prevention.

"Clearly there are a lot of new technologies and approaches, and a lot of them can help. But when we look at the big picture, what we can do right now is focus more on smoking, exercise and nutrition," he says.

More than 1.3 million Americans are expected to get cancer this year, according to the American Cancer Society. Due to an aging population, the number is rising despite declines in deaths from the four main cancers -- lung, colon, breast and prostate.

About two-thirds of all cancers, however, could have been prevented based on lifestyle choices, Lichtenfeld says.

"There are huge returns in getting people to be healthy, stopping smoking and getting regular screenings," he says.

There have also been major advances in cancer detection.

The use of molecular testing, for instance, now allows doctors to find the smallest amounts of cancer in a person's body. Although this helps doctors to monitor cancer patients in remission to ensure the disease doesn't come back, it may also help detect cancer earlier in seemingly healthy people.

Traditionally, doctors had used microscopes to detect cancer cells. But this technology is inexact by today's standards, says Dr. Jerald Radich, a researcher with the Fred Hutchinson Cancer Research Center in Seattle.

Using a microscope, cancer cells aren't visible unless there are lots of them -- about one tumor cell to 100 healthy cells. Molecular testing, by contrast, can find one tumor cell in a million healthy cells, leading to earlier detection and treatment, Radich says.

Many of the advances in cancer treatment result from research on leukemia. The reason is fairly simple, Radich says. Because leukemia resides in the blood, it is easier to extract and study than cancers that reside in tissue. Leukemia research gained momentum in the 1970s, while research on other cancers lagged behind, he says.

But once researchers unlock the secrets of other cancer genes, a new set of questions may arise, Lichtenfeld says. For example, as targeted drugs become more refined, they may also become prohibitively expensive to develop.

Lichtenfeld is also concerned that use of new therapies might outpace safety testing. A few years ago, for example, doctors thought bone marrow transplants might help women with breast cancer, but it wasn't until many of them had gone through this painful procedure that tests showed it didn't really help, he says.

"Hand-in-hand with all of this wonderful technology is the question how to use it. If you don't concentrate on how to use it early on, you may have to play catch-up for many years. You don't want it used haphazardly," Lichtenfeld says.

More information

For detailed guidelines about preventing cancers, visit the National Cancer Institute. Or visit this site by the U.S. Centers for Disease Control and Prevention.

SOURCES: Len Lichtenfeld, M.D., Cancer Control Science Department, national office, American Cancer Society, Atlanta; Jerald Radich, M.D., Fred Hutchinson Cancer Research Center, Seattle; Peter Maslak, M.D., chief, hematology laboratory, Memorial Sloan-Kettering Cancer Center, New York City

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