THURSDAY, July 31 (HealthDay News) -- Scientists have taken a step forward in understanding the mechanisms behind a problem that has bedeviled many men, and some women, for all of history: hair loss.
The study identifies a key signaling molecule that tells hair follicles to start the hair-growing cycle.
"These are very complex molecular signals, and the authors have very nicely shown that there is one molecule, laminins 511, that is a very important signal to tell the hair molecule to move through the process. It's part of a basic biological understanding," said Dr. Ronald Crystal, chairman of genetic medicine at New York Presbyterian Weill Cornell Medical Center in New York City.
The researchers, reporting in the Aug. 1 issue of Genes & Development, feel the findings may one day hold the key to treating male-pattern baldness, as well as hair loss from chemotherapy or even to restore hair on burn victims.
But, as so often happens, the study was conducted in mice and, as Crystal pointed out, "Mice are not just little men and women. They are different than us and also different in their hair."
A series of complex molecular signals tell hair follicles to go through a cycle of follicle growing, hair growing, follicle receding and hair receding, Crystal explained.
The same group of researchers had previously found that the protein laminin-511 was important to hair development.
In this study, the authors found out why. It was originally thought that laminin-511 was made from the cells of the outer layer of the skin (epithelium) and acted on the epithelium.
It now turns out, however, that the protein, although produced by the epithelium, actually penetrates into the inner layer of the skin (dermis) to kick start the hair-growing process.
"So laminin-511 is an early epithelial message to the dermis to say let's start producing hair," said study senior author Dr. Peter Marinkovich, an associate professor of dermatology at Stanford University School of Medicine and member of the Stanford Cancer Center. "Hair is formed as a result of cooperation and communication between the two layers."
"We knew that the two layers of the skin are important in hair formation, and we knew that there was some early epithelial signal hypothesized a long time ago, but no one knew what it was until now," he added.
In mice, laminin-511 convinced hair to grow at the equivalent of about the eighth month of pregnancy, but Marinkovich and his colleagues are hoping it might also work later in the life cycle.
Male baldness associated with aging would be an obvious target. "The hair follicles are still there, but they get stuck in the cycle, so it's not well understood why they're stuck and . . . how do you get them unstuck," Crystal said. "The hope, of course, is that you can apply this to humans, but there are some cautions in all that. Biology is very complex. There are a lot of checks and balances. You don't want hair follicles and cells in hair follicles to be growing too much or not enough. The on-and-off signals that are dampening that and controlling that are very, very complex and not well understood. This is far, far from humans."
More information
For more on male-pattern baldness, visit the U.S. National Library of Medicine.
FRIDAY, Nov. 2 (HealthDay News) -- A variant of a gene that doubles the risk of prostate cancer in black men has been identified, and researchers say the discovery could lead to new treatments.
Almost twice as many black men develop prostate cancer as white men, researchers report. This study confirms that common genetic variants are linked to increased risk for prostate cancer. One of these variants, on the 8q24 gene, confers a particularly significant risk to black men.
"We found a gene involved in increased risk for prostate cancer in African-Americans," said lead researcher Rick Kittles, an associate professor of medicine at the University of Chicago. "This gene is involved in DNA repair."
In the study, Kittles' team looked at the 8q24 region of chromosome 8 and compared genotypes of 490 black men with prostate cancer to 567 controls.
Their report was published in the Oct. 31 online edition of Genome Research.
Finding these variants enables researchers to find out how the gene works in prostate cancer, Kittles said. "We hope to find more treatment options, or even prevention," he added.
"This gene is not exclusive to African-Americans," Kittles stressed. "This variant may be in higher frequency in African-Americans, but it's not exclusive to African-Americans."
Kittles' team is looking at this variant in other populations to try to determine how much of a role it plays in the risk for prostate cancer in other groups of men. "We know the variant is there. We need to see if it is involved in prostate cancer risk in these populations, too," he said.
Prostate cancer is the second leading cause of cancer death among men. This year, 27,000 men in the United States will die from the disease, according to the American Cancer Society. Black men have the highest rates of prostate cancer worldwide.
One expert thinks this study adds to an understanding of prostate cancer but has no immediate clinical application.
"It is encouraging that we are starting to identity some of these regions on the human genome that may be associated with an increased risk for prostate cancer," said Dr. Durado Brooks, director of prostate and colorectal cancer at the American Cancer Society. However, "it is unlikely that this is the only one," he added.
This variant doesn't seem to be associated with the aggressiveness of the disease, Brooks said. "It's important, but we are still a long way from having any strong clinical applicability from these findings," he said.
More information
For more on prostate cancer, visit the U.S. National Cancer Institute.