December 2025: Carmit Levy: New study reveals how melanoma disarms the body’s defenses

A new international study led by Prof. Carmit Levy, Edmond J. Safra affiliate (Medical & Health Sciences), and published in Cell, has uncovered a previously unknown strategy melanoma tumors use to disable the immune system.

Prof. Levy and her team discovered that melanoma cells release tiny bubble‑like particles called extracellular vesicles (or melanosomes). These particles bind to immune T‑cells, the very cells tasked with killing cancer cells. Once attached, the vesicles confuse and weaken the T‑cells, leaving them unable to destroy the tumor.

The researchers also found that these vesicles camouflage themselves with the same molecules found on melanoma cells. This tricks the immune system, causing many T‑cells to bind to the decoy vesicles rather than to the real tumor, becoming exhausted or dying. This may help explain why 40–50% of melanoma patients do not respond to immunotherapy, even when their tumors contain many immune cells.

Experiments in mice showed that when the release of these vesicles is blocked, more T‑cells are able to reach the tumor, and tumor growth slow significantly, suggesting a promising direction for future treatments.

This major breakthrough was achieved through a large international collaboration involving teams from Sheba Medical Center, the Weizmann Institute of Science, the University of Liège, the Technion, Massachusetts General Hospital, the Hebrew University, and others. This discovery could pave the way for new therapeutic strategies that either strengthen immune cells against melanoma’s decoy attack or block the vesicles altogether, making the cancer more vulnerable to treatment.

The study received wide media coverage: JPOST, DOCTORSONLY ,Bioquicknews, Agenciaajn, daily27, Israeleconomico, juedische-allgemeine, baohaiphong, lapaginajudia, ITONGADOL, and more.