Oct. 9 (UPI) -- Individuals with an inherited form of melanoma responded well to immunotherapy in a small trial in Sweden.
Researchers from Karolinska Institute in Sweden studied people with melanoma who carry mutations in CDKN2A gene and have poor prognosis, and whether drugs given as intravenous infusion effectively reduce or even eliminate tumors.
The findings were published Friday in the Journal of Medical Genetics, four days after James P. Allison and Tasuku Honjo were awarded the 2018 Nobel Prize in Physiology or Medicine for discovering therapies that work by harnessing the body's own immune system to find and destroy cancer cells.
"We saw that the mutation-carriers with metastatic melanoma responded surprisingly well to immunotherapy," study leader Dr. Hildur Helgadottir, a researcher at the Department of Oncology-Pathology at Karolinska, said in a press release. "This is good news, particularly for this otherwise vulnerable patient group."
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Melanomas usually start on the chest and back in men and on the legs in women, according to the American Cancer Society. The neck and face are other common sites.
Each year about 91,270 new melanomas will be diagnosed in the United States -- 55,150 in men and 36,120 in women, according to the American Cancer Society. About 5,990 men and 3,330 women are expected to die of melanoma each year.
Melanoma is more than 20 times more common in white people than in African Americans and the risk increases as people age. The average age is 53 at diagnosis.
When Melanoma has metastasized, there has been limited response to traditional chemotherapy.
The researchers compared their findings with previous large-scale studies in which melanoma patients were treated with immunotherapy. In treating cancer, these immune checkpoint inhibitors brake mechanisms in the immune system.
"Our conclusion from the study is that CDKN2A mutation carriers with metastatic melanoma have good chances of responding to immunotherapy, which can be associated with the fact that tumors with a CDKN2A mutation seem to have a tendency to accrue even more mutations, although this relationship requires further investigation," Helgadottir said.
In the study, 11 of the 19 patients with CDKN2A mutations -- 58 percent -- responded to the treatment with shrinking tumors. In six of patients, they disappeared completely.
In earlier clinical studies, just over one-third responded to the treatment, and tumors disappeared totally in only one of 15 patients.
The researchers also found that melanoma tumors with CDKN2A mutation had a larger number of mutations compared with tumors without CDKN2A mutation. The researchers believe this is because CDKN2A mutated tumor cells become so unlike healthy cells that the immune system finds them easier to recognize as foreign.
