DNA treatment helps stop melanoma

June 8, 2011 9:46:27 AM PDT
For the first time in years, patients with advanced melanoma may have some effective treatment options.

Melanoma, the most serious type of skin cancer, develops in the cells that produce melanin -- the pigment that gives your skin its color. Melanoma can also form in your eyes and, rarely, in internal organs, such as your intestines.

Melanoma accounts for less than 5 percent of skin cancer cases but a majority of skin cancer deaths. Melanoma is the fifth most common cancer among men and the seventh most common cancer in women. Sometimes, melanoma is found in children and teenagers.

The exact cause of all melanoma is not clear, but exposure to ultraviolet (UV) radiation from sunlight or tanning lamps and beds increases your risk of developing the cancer. Other factors, such as your genetic makeup, likely also play a role. (SOURCE: Mayo Clinic)

STANDARD TREATMENT: People with melanoma may have surgery, chemotherapy, biological therapy, or radiation therapy. Patients may have a combination of treatments. At any stage of disease, people with melanoma may have treatment to control pain and other symptoms of the cancer to relieve the side effects of therapy and to ease emotional and practical problems. This kind of treatment is called symptom management, supportive care, or palliative care. (SOURCE: Medicinenet.com)

NEW ANSWERS: Scientists from The Institute of Cancer Research (ICR) showed that in human cancer cells and mice, a gene called BRAF -- which is damaged in about half of all skin cancer cases -- triggers a cell signaling pathway that ultimately "blocks the instructions" from a second gene called PDE5A.

In healthy cells, PDE5A acts as a brake to stop cell movement. However, in cancer cells, BRAF turns PDE5A's signals off, removing its ability to block cancer spread.

By blocking the activity of PDE5A, BRAF drives skin cancer cells to invade new tissues and spread further around the body, converting skin cancer into a more aggressive disease. BRAF is only expressed in 8 percent of cancer but 50 percent of melanomas. BRAF inhibitors like PLX4032 (vemurafenib) inhibited proliferation of tumor cell lines, a mutation found in several human cancers including melanoma.

The compound also showed partial or complete tumor regression and improved survival in a dose-dependent manner in preclinical efficacy models in rodents, without associated toxicity.

"What's really exciting is that there are new drugs, new inhibitors that target these genes. They can put the brakes on these rapidly-dividing cells," Lynn Schuchter, M.D., Chief of Hematology and Oncology at the Abramson Cancer Center at the University of Pennsylvania, told Ivanhoe. (SOURCE: American Association of Cancer Research)


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