The U.S. Food and Drug Administration has approved the use of Cotellic in combination with Zelboraf for the treatment of advanced melanoma. Pictured: A woman puts sunscreen on the arm of a young girl at a beach in Fort Lauderdale, Florida. Getty Images/Joe Raedle

Researchers at Tel Aviv University, Israel, identified the trigger behind the transformation of melanoma cancer cells from non-invasive cells to destructive killers. The team found that melanoma, the most dangerous form of skin cancer, results from an uncontrolled division of melanocytes, melanin-producing cells located in the bottom layer of the skin's epidermis.

“Melanoma is a cancer that originates in the epidermis, and in its aggressive form it will invade the dermis, a lower layer, where it eventually invades the bloodstream or lymph vessels, causing metastasis in other organs of the body. But before invading the dermis, melanoma cells surprisingly extend upward, then switch directions to invade,” lead author Carmit Levy of the department of human genetics and biochemistry at the university’s Sackler School of Medicine, said in a statement released Monday.

Levy explained that if melanoma cells are stopped before they travel downward, the cancer progression could be halted. Melanoma, which affects about 2 percent of Americans, is the leading cause of skin cancer deaths in the country, according to the American Cancer Society.

In order to find what causes melanoma cells to spread to the dermis, researchers gathered normal skin cells and melanoma cell samples from hospitals across Israel. They conducted gene expression analysis to examine the behavior of the cancer cells.

The study showed that the direct contact of melanoma cells with the remote epidermal layer causes an invasion through the activation of ‘Notch signaling’ that switches on a set of genes, setting off the transformation of melanoma cells into an invasive, lethal agent.

“There are many drugs in existence that can block the Notch signaling responsible for that transformation. Maybe, in the future, people will be able to rub some substance on their skin as a prevention measure," Levy said.

The study was published Thursday in Molecular Cell journal.