Genetic Tests Show How Moles Turn Cancerous
Scientists are able to tell whether a suspect mole will become malignant or not, according to TODAY.
They confirm that people with moles should beware of the sun. If the skin is exposed to ultraviolet radiation, then it leads to genetic mutations that lead to a mole turning into melanoma, according to the New England Journal of Medicine.
"Ultraviolet radiation turns moles into melanoma," said Dr. Boris Bastian of the University of California San Francisco, a pathologist who was one of the leaders of the probe.
Studying 37 patients around the world whose moles became malignant, Baines with his team of researchers sequenced the DNA in the tumors and compared it with DNA from healthy tissue taken from the tumor to see that the cancer cells are removed.
While all moles have some genetic mutations, they are not all dangerous.
"The melanomas invariably had additional genetic mutations," said Bastian.
However, these mutations expand with time. There are additional mutations in some parts of the mole that are benign, not yet cancerous.
"What we have shown is those alterations can be found in the benign precursors," Bastian said. That means melanoma is similar to other forms of cancer, such as colon cancer or cervical cancer, which start with benign growths that can progress to cancer.
The study shows there is an intermediate zone between the moles that become malignant, and it is determined by the number of mutations you have, and what kind they are.
Normally, moles undergo a mutation called BRAF V600E, which then take on more mutations before they turn malignant.
"What we can find is these secondary and tertiary mutations that came after the mole formed and that make the mole progress to melanoma are caused by radiation," Bastian said.
"The overwhelming majority of moles do not turn into melanoma. You need all the pathogenic mutations, and you have to have all those mutations in the same cell. That is highly unlikely to occur."
The main reason it happens is exposure to sulight.
"By exposing yourself to UV radiation, you are forcing your bad luck," Bastian said.
While melanoma is the "deadliest form of skin cancer", according to the National Cancer Institute, "74,000 Americans will be diagnosed with melanoma and nearly 10,000 will die from it this year".
Currently, people have huge chunks of skin cut out from their bodies if they have ugly moles. Bastian is hoping that genetic tests can save people, according to TODAY.
"Right now we practice defensive medicine," Bastian said. "When in doubt, cut it out."
The practice can also help people who have melanoma which is not too obvious. By removing a suspicious-looking mole, but with mutations that indicate that it is getting cancerous, doctors can remove the surrounding tissue too and test the nearby lymph nodes to help the skin.
Such tests are helping to detect and treat cancer earlier, said two experts on the genetic testing of tumors, Dr. Bert Vogelstein and Dr. Kenneth Kinzler of the Howard Hughes Medical Institute and Johns Hopkins University.
With new drugs, the genetic mutations making the tumors dangerous can be treated instead of destroying a whole lot of cells.
"It's a whole new ball game," they wrote.