Jerusalem, 29 December, 2025 (TPS-IL) — Israeli and international scientists have uncovered a surprising way that melanoma, the deadliest form of skin cancer, disables the body’s immune defenses, a breakthrough that could lead to new treatments, Tel Aviv University announced.
Melanoma is relatively common compared with other types of skin cancer. However, it causes roughly 57,000 deaths globally per year, making it the deadliest form of skin cancer, according to the World Health Organization. Around 325,000 new cases of melanoma are diagnosed worldwide each year.
The study, published in the peer-reviewed journal Cell, shows that melanoma cells release tiny bubble-like structures called extracellular vesicles, or EVs, which can paralyze the immune cells that normally attack tumors.
The international study was led by Prof. Carmit Levy of the Department of Human Genetics and Biochemistry at TAU’s Gray Faculty of Medical & Health Sciences, in collaboration with teams from Sheba Medical Center, the Weizmann Institute of Science, the Technion, Tel Aviv Sourasky Medical Center, Wolfson Medical Center, Massachusetts General Hospital, Hadassah Medical Center, the Hebrew University of Jerusalem, Rabin Medical Center, Paris-Saclay University, and the University of Zurich.
Melanoma begins when pigment-producing cells in the skin divide uncontrollably. As the cancer grows, it can invade deeper layers of skin and spread to other parts of the body through the blood and lymphatic systems. Previous research by Prof. Levy had shown that melanoma cells release large EVs, called melanosomes, which help the cancer spread. However, the new study reveals an even more alarming function: these vesicles can actively neutralize the immune cells that are sent to destroy the tumor.
“We began studying these vesicles, and I noticed that on the vesicle membrane there was a molecule—a ligand—that binds to a receptor found only on certain immune cells called lymphocytes, specifically those that can kill cancer cells,” Levy explained. “I then hypothesized that this ligand latches onto the attacking lymphocytes, effectively paralyzing them. It was an unusual idea, but the lab experiments confirmed it.”
At that point, Levy invited colleagues around the world to help study this.
“And the result is remarkable: the cancer essentially fires these vesicles at the immune cells, stopping them from working and sometimes even killing them,” Levy noted.
“We have a lot of work ahead of us, but it’s clear that this finding could have major therapeutic implications,” she said. “It opens two paths: we can strengthen immune cells so they can resist the melanoma’s attack, or we can block the vesicles from binding to them, leaving the cancer exposed. Either approach could lead to new, more effective therapies.”
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