By Merritt McKinney

NEW YORK (Reuters Health) - A compound derived from a type of lily holds promise as a treatment for several types of cancer, including basal-cell skin carcinoma, the most common form of cancer, researchers report.

Although the compound, cyclopamine, has not been tested on cancer cells yet, in laboratory tests, it blocked the growth of cells that have undergone genetic changes that also occur in basal-cell skin cancer tumors, the study's lead author told Reuters Health.

Conventional cancer treatments cut a wide swath in the body, obliterating all sorts of growing cells, according to Dr. Philip A. Beachy, of Johns Hopkins University School of Medicine in Baltimore, Maryland.

Such treatment can destroy rapidly proliferating cells in cancerous tumors, but it can also kill off healthy hair and intestinal cells, he explained. The latest approach to cancer treatment is ``to attack cancer cells specifically by affecting pathways that are operating in those cells and are unique to these cells,'' Beachy said.

That is exactly what cyclopamine appears to do, Beachy and his colleagues report in the August 31st issue of the journal Nature.

Basal-cell carcinoma cells grow very slowly, making it difficult to culture them in the lab, so the researchers substituted cells engineered to have the same genetic mutations as skin cancer cells, according to Beachy.

In lab tests, doses of cyclopamine that did not affect normal cells stopped the genetically engineered cells from growing.

The findings suggest that cyclopamine may prove useful in treating basal-cell carcinoma, but the researcher said that the greatest potential benefit might be for people with other tumors that display similar genetic changes.

Because basal-cell skin cancer grows extremely slowly, it is usually possible to remove the cancer surgically before it spreads, Beachy explained. But other types of cancer, including medulloblastoma, a type of childhood brain cancer, may respond to cyclopamine, he noted.

Beachy cautioned that the compound has not been tested in people yet. ``We haven't treated actual tumor cells,'' he said. ''We don't know what the effects of treating real tumors will be.''

But he said, ``At least we have a tool to see whether blocking this pathway can block tumors or even kill tumors.''

An expert at Yale University School of Medicine in New Haven, Connecticut, agrees that it is too soon to conclude that cyclopamine will work as a cancer treatment.

Using the compound to shut off the...pathway in basal-cell skin cancer cells ``might be like shutting the barn door after the horse has bolted,'' Dr. Allen E. Bale writes in an editorial that accompanies the study.

This treatment may slow down or stop the growth of tumors, but it may not kill them, according to Bale. Once treatment is stopped, the tumors may start growing again, he notes.

And since cyclopamine is known to damage the fetuses of pregnant sheep, studies of any drug derived from the compound should not include women of childbearing age, according to Bale.

(From Yahoo)