"We're seriously considering moving to humans," says the leader of the research effort, Dr. Ronald G. Crystal. Crystal heads the Institute of Genetic Medicine at Weill Medical College of Cornell University.
About 85 percent of patients getting chemotherapy go bald because the drugs attack fast-growing cells, and the follicles from which hair grow fall into that category. Hair loss starts two to three weeks after treatment begins, and it can take up to a year for hair to regrow. In some patients, new growth never happens.Any treatment that allows patients to keep their hair would not only provide a major psychological boost but also would help save lives, says Dr. LaMar McGinnis, a senior medical consultant for the American Cancer Society.
"This visible aspect of cancer therapy is very disturbing to a larger percentage of patients," McGinnis says. "I've had patients tell me it is the hardest part of going through cancer therapy. Some patients can decline to have chemotherapy because of the fear of hair loss."
The gene that Crystal and his colleagues are using was first identified in fruit flies. It is called Sonic hedgehog (Shh), because a mutation causes an embryo to look like a curled-up hedgehog. It plays an important role in the formation of essential organs, including the brain, heart, lung and skeleton.
"We know that if you knock out the gene in mice, they have no hair," Crystal says. "It is expressed in hair follicles, where it acts as a master switch gene that turns on the hair follicles to grow. We know that in chemotherapy, the hair follicles get damaged, so we thought that if you give a genetic boost to the follicle, you could get hair to grow."
A report in the Dec. 19 issue of the Journal of the National Cancer Institute says the Shh gene was packaged in a harmless version of a cold virus and was injected into the skin of mice who had gone bald after they were given the cancer drug cyclophosphamide. Two weeks after the injection, the follicles of the mice were in an active growth phase, the researchers say.
The transition to human trials should not be difficult, although many details must be worked out, Crystal says. "We've done the safety studies, and it would probably take a couple of years to get to human studies," he says.
The American Cancer Society has been working to solve the problem, but with limited success, McGinnis says. "A few years ago we were trying cooling the head, with a turban to cool the scalp," he says. "It does slow hair loss somewhat, but it has been abandoned."
In addition to the gene therapy work by Crystal, another approach to preventing hair loss is being tried by researchers at the drug company Glaxo Wellcome, McGinnis says. They are working on increasing the activity of an enzyme that promotes hair growth, which is damaged by chemotherapy.
"These two approaches show that now we are in the era of molecular therapy," he says. "We are addressing issues like this on a molecular level. It may take some time, but everyone hopes that this will work. Therapies are coming forward at a rapid rate."
What To Do
The American Cancer Society offers advice about makeup and the use of wigs and turbans to "make people feel better and enhance their sense of well-being" through its "Look Better, Feel Better" program, McGinnis says.