Teams of scientists discover gene responsible for common skin cancer

June 14, 1996|By KNIGHT-RIDDER NEWS SERVICE

WASHINGTON -- A gene responsible for the most common type of cancer in humans has been found, two international teams of scientists reported yesterday.

When the gene is damaged by ultraviolet radiation from the sun, it can produce skin tumors, known as basal cell carcinomas, that afflict about 750,000 people in the United States each year.

Pale-skinned, middle-aged and older persons of Northern European ancestry are the most susceptible to these relatively harmless growths. If caught in time, they are easily removed with minor surgery or radiation.

The discovery of the new gene could lead to the development of a less-invasive treatment by a drug or ointment applied directly to the skin, scientists said.

Dr. Ervin Epstein Jr., a dermatology professor at San Francisco General Hospital, belongs to a group of scientists, based in California and London, who reported their findings in the journal Science. Simultaneously, a rival team composed of Australian, Swedish and American scientists published a similar report in the journal Cell.

Both groups were seeking the source of a rare -- but virulent -- related disease known as basal cell nevus syndrome, which mostly affects children who have been exposed to the sun. Also known as Gorlin syndrome, its symptoms include cysts in the jaw, extra fingers and abnormal ribs and vertebrae, as well as hundreds of skin tumors.

From previous studies of fruit flies, scientists knew that a gene called "patched" helps to control the growth of cells in flies. When "patched" is missing or defective, flies develop faulty wings or other abnormalities.

The research teams found an almost identical human gene on chromosome 9, one of the 23 pairs of chromosomes that carry the DNA, the genetic code of life, in every cell.

Analysis showed flaws in the "patched" genes of persons with the nevus syndrome and basal cell carcinoma, indicating that this defect is connected with both diseases. The gene turns out to be a "tumor suppressor," a molecular brake that is supposed )) to keep cells from multiplying out of control -- in other words, from becoming cancerous.

Pub Date: 6/14/96

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