Melanoma cells produce a large variety of extracellular vesicles(EVs). Purpose of this study is the evaluation of the diagnostic potential role, like predictive biomarkers of circulating EVs in peripheral blood in patients with primary and metastatic melanoma. The sample was collected by taking a blood sample before surgical removal of lesions suspected of melanoma in order to avoid artifacts due to surgery: overall it was composed of 77 consecutive patients, 12 affected by primary cutaneous melanoma, 8 by metastatic melanoma and 57 healthy controls. Diagnosis of Melanoma and staging were performed after the blood collection. Sample was collected and analyzed, with a specific method for EVs. Different subpopulations were studied using two different panels: Panel I(Melanoma-Specific EVs) CD45; CD90; CD117 and Panel II(Immune-Checkpoint EVs) CD45; PD-L1; VISTA. The total number of EVs was higher in patient affected by melanoma than in controls(3299,86±456,61 MV/ul vs 2873,4±427,74 MV/ul; p=0.047). The total number of EVs PDL-1+ or CD45+ or PD-L1+ CD45+(leukocyte derived EVs) was higher in patient affected by melanoma than in controls(EVs PDL-1, p=0.004; EVs CD45+, p<0.001; PD-L1+ CD45+ p<0.001). The total number of EVs CD45+ VISTA+ was higher in patient affected by melanoma than in controls(65,678±49,5473 vs 20,321±6,7312; p=0.031). In conclusion, the total number of EVs and total number of leukocyte derived EVs may be considered as potential markers of melanoma and potentially used in the follow up. The EVs derived from activated myeloid cells (CD45+ VISTA+) infiltrating the melanoma are increased in patient with melanoma with a possible correlation of VISTA in the suppuration of T-cell in the progression of tumor. The EVs PD-L1 can be potentially used in the study of identification of immunotherapies responsive patients.

ESDR475 - Diagnostic potential of circulating extracellular microvesicles in patients with primary and metastatic melanoma

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.