News Story in the Union-Tribune, February 2, 2004
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Scientists can profile prostate's cancer cells
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Genes help guide level of treatment
By Bruce Lieberman
STAFF WRITER
Scientists in La Jolla have found a way to distinguish different types
of cells in prostate tumors, an advance that may allow them to recognize
aggressive forms of prostate cancer from more benign types that do not
require surgery.
The researchers, studying prostate tissue samples taken from 41 men diagnosed
with the cancer, identified genes that are activated in three major types
of cells found in the prostate, including malignant tumor cells.
"The methods developed here will allow us to distinguish indolent
disease that does not need surgery from aggressive disease that needs
immediate intervention," said Dan Mercola, a researcher at the Sidney
Kimmel Cancer Center in La Jolla and a principal investigator on the project.
The study, which appeared recently in the Proceedings of the National
Academy of Sciences, was a collaboration among the Kimmel cancer center,
the Veterans Affairs San Diego Healthcare System, the University of California
San Diego and the Ludwig Institute for Cancer Research.
In their study, the scientists found that different types of cells within
the tumor expressed, or activated, different messenger RNA molecules,
the molecules that guide the synthesis of proteins according to the genetic
instructions stored in DNA.
Prostate tumors contain both malignant and nonmalignant cells, so the
ability to distinguish between the two is critical for understanding how
aggressively the cancer is growing, the researchers said.
By measuring the genes within the cells of a tumor, scientists can create
a "gene expression profile" that could allow doctors to more
accurately advise patients of their treatment options.
A test may be available to physicians for clinical trials within a year,
Mercola said.
Prostate cancer is a disease of the cells lining the glands of the prostate,
the golf-ball-sized organ at the base of the bladder in men.
Some 230,110 men in the United States will be diagnosed with prostate
cancer this year, according to the American Cancer Society.
Nearly 30,000 will die this year from the disease. It is second only
to lung cancer as the cause of cancer-related deaths among U.S. men.
The current procedure for diagnosing prostate cancer is a measure of
prostate-specific antigen, or PSA, in the blood. But it is not as predictive
as scientists would like, telling neither how advanced the cancer is nor
indicating how fast it may grow.
Unneeded surgery, which carries several risks, can make life miserable
for patients.
"Since most cases of prostate cancer are of the indolent variety,
a great deal of curative surgery could be avoided," Mercola said.
A reliable genetic test that could help men avoid risky surgery "is
absolutely necessary," said Dr. Otis Brawley, associate director
for cancer control at the Winship Cancer Center at Emory University in
Atlanta.
Too few patients are told of the questions the PSA blood test leaves
unanswered, as well as the risks associated with surgery, Brawley has
said.
"The problem with prostate cancer screening is there is evidence
that more than two-thirds of those diagnosed through screening likely
do not need treatment, and we currently treat them all with all the incumbent
side effects of treatment, (including) the mental anguish of a cancer
diagnosis, possible incontinence, impotence and even death," Brawley
said. "Any test to distinguish the prostate cancers that need treatment
versus those that need to be watched and may be even ignored is a tremendous
advance."
The National Institutes of Health funded the study as part of a program
designed to use human gene sequence information to determine which genes
play a role in cancer.
Co-authors of the article include Karen Arden, Charles Berry, Steven
Goodison, Iveta Kalcheva, Igor Klacansky, Dan Masys, Michael McClelland,
Ann Sawyers, Robert O. Stuart, David Tarin, William Wachsman, Jessica
Wang-Rodriguez, Yipeng Wang and Linda Wasserman.
