Genetic Mutation May Be Key To Onset Of Deadly Skin Cancer Posted Friday, August 17, 2001 by ctustis
A Johns Hopkins scientist and a team of collaborators have discovered how
precancerous moles may progress to melanomas, the most deadly type of
skin cancer. The preliminary report, in the August 15 issue of Cancer
Research, describes a link between two genes that trigger skin cancers
and could serve as early diagnostic markers for the disease. The
researchers say that, in melanomas, a cell growth regulatory gene known
as Id1 deactivates an important tumor suppressor gene (p16/Ink4a),
allowing cancer cells to grow uncontrollably.* High levels of Id1
proteins are found only in the first stages of melanoma, allowing it to
be detected and treated while still in a curable stage. trigger skin
cancers and could serve as early diagnostic markers for the disease.

"Telling the difference between precancerous moles and early-stage
melanoma can be very difficult, and the treatments for these two lesions
differ significantly," explains Rhoda Alani, M.D., assistant professor of
oncology, dermatology, molecular biology and genetics and director of the
study. "If it's melanoma, you want to catch it very early and treat it
aggressively by removing as much tissue as possible to cure the disease."
Since Id1 is expressed in early-stage melanoma, it has the potential to
serve as a definitive diagnostic marker although more studies are needed
to confirm this use.trigger skin cancers and could serve as early
diagnostic markers for the disease.

The scientists studied Id1 protein expression in 21 tissue samples from a
variety of skin cancers, including normal non-cancerous moles (benign
nevus), precancerous moles (dysplastic nevus), early-stage melanoma
(in-situ melanoma), invasive melanoma and metastatic melanoma. "We found
high levels of Id1 activity in the earliest phases of melanoma, when it's
limited to the top layer of the skin (or epidermis). Precancerous moles,
invasive and metastatic melanomas do not express high levels of Id1,"
reports Alani. Larger studies are planned.trigger skin cancers and could
serve as early diagnostic markers for the disease.

The scientists speculate that while the Id1 gene shuts off p16/Ink4a in
early melanomas and lifts the brake on uncontrolled cancer cell growth,
various mutations or other DNA changes must also occur to the p16/Ink4a
gene to damage it beyond repair. So, as the cancer progresses, Id1
becomes less important for shutting off the gene. "This may explain why
we see lower expression of Id1 in more advanced melanomas," says
Alani.trigger skin cancers and could serve as early diagnostic markers
for the disease.

Melanoma can progress very rapidly and spread to other parts of the body.
When treated early, the chance for cure is very high. Only 12 percent of
people with metastatic melanoma survive beyond five years.trigger skin
cancers and could serve as early diagnostic markers for the disease.

Melanoma will strike 51,400 people in the United States this year, and
7,800 will die from the disease.trigger skin cancers and could serve as
early diagnostic markers for the disease.

In addition to Alani, other participants in this research include David
Polsky from NYU Medical Center; Alison Zuyung Young and Klaus J. Busam
from Memorial Sloan-Kettering Cancer Center. This research was funded by
The National Institute of Arthritis, Musculoskeletal and Skin Diseases
(NIAMS).trigger skin cancers and could serve as early diagnostic markers
for the disease.

Note: This story has been adapted from a news release issued by Johns
Hopkins Medical Institutions for journalists and other members of the
public. If you wish to quote from any part of this story, please credit
Johns Hopkins Medical Institutions as the original source. You may also
wish to include the following link in any citation:
http://www.sciencedaily.com/releases/2001/08/010815082241.htm
Source:Johns Hopkins Medical Institutions (http://www.hopkinsmedicine.org/)

Date:Posted 8/16/2001