ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Friday, June 14, 1996 TAG: 9606140030
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
DATELINE: WASHINGTON
SOURCE: Associated Press
NOTE: Above
750,000 AMERICANS are diagnosed with basal cell carcinoma - skin cancer - each year. Two separate research teams have found its source.
Research blending genetic studies of fruit flies and human beings has identified the mutated gene that causes basal cell carcinoma, a skin tumor that is the most common form of cancer.
Two teams of researchers, working independently, found that the mutation of a gene called ``patched'' allows the uncontrolled growth of cells in the skin, forming a type of cancer that strikes about 750,000 Americans a year but is seldom lethal.
The same gene mutation, when inherited, was identified as the cause of basal cell nevus syndrome, or BCNS, a rare disorder that causes a variety of symptoms, including skin cancers, abnormal bone development, jaw cysts and spinal defects. BCNS affects between 1 in 57,000 and 1 in 164,000 people.
Reports on the discoveries will be published today in the research journals Science and Cell.
A California team led by Matthew P. Scott, a Howard Hughes Medical Institute researcher at Stanford University, identified the patched gene in the fruit fly and found that its mutation caused developmental problems in the insect.
Guided by the fruit fly gene pattern, Scott's group located the patched gene in mice and then in men.
Scott learned that Dr. Ervin H. Epstein Jr., a University of California, San Francisco, dermatologist, was leading a search for the gene that causes BCNS. He contacted Epstein and suggested that patched may be the BCNS gene.
The two groups combined their efforts and confirmed that people with BCNS did, in fact, inherit the mutated patched gene.
They also found that the same gene was present in basal cell carcinoma tumors, the skin cancer that is caused by excessive exposure to sunlight. When non-tumor cells in patients with skin cancer were tested, the researchers found a normal patched gene. This supported the idea that ultraviolet rays from the sun can cause the mutation that leads to skin cancer, the researchers said.
A report on the Scott and Epstein research is to be published in Science.
An international team of researchers, led by Allen E. Bale of Yale University, also identified the patched gene and related it to both BCNS and to the more common basal cell carcinoma. This research is to be published in Cell.
Discovery that the patched gene regulates embryo development before birth and cell division later in life suggests that it may be fundamental in the understanding of cancer, said Dr. Richard Klausner, director of the National Cancer Institute.
``It's going to tell us a great deal about cancer and human development,'' he said in a statement.
Scott said that patched has apparently been a part of the genetic pattern of life for millions of years because it is present virtually unchanged in fruit fly, mouse and human being, creatures separated by eons of evolution.
``Some of the genes we study are doing the same thing in human and in fruit fly,'' Scott said.
The paired patched gene's role is to regulate cell growth by helping to turn off another gene, called hedgehog, that triggers cell division. People who inherit one mutated copy of the patched gene have birth defects, mostly affecting the bones. Two mutated or missing patched genes can lead to rapid development of skin cancer.
The normal patched gene prevents runaway cell growth throughout life. Researchers believe if the gene is mutated in skin cells by excessive sunlight, then spontaneous tumors can develop. This type of cancer grows slowly and usually is controlled with surgery. But left untreated, the skin cancer can cause widespread destruction of tissue, often on the face.
It is different from squamous cell carcinoma, another type of skin cancer, which is more likely to spread but is also usually controlled by surgery. A more frequently lethal and less common skin cancer is malignant melanoma, which can spread rapidly and invade a number of other tissues.
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