88P Head, neck and shoulder desmoid-type fibromatosis: characteristics and outcome of these ultra-rare locations

Results: Cohort1 (253 patients) included undifferentiated pleomorphic sarcoma (UPS), myxofibrosarcoma (MFS), synovial sarcoma (SS), leiomyosarcoma (LMS), dedifferentiated liposarcoma (DDLPS) and malignant peripheral nerve sheath tumor (MPNST).12 % (31/253) exhibited amp of NECTIN4.The UPS group comprised 50 cases with 11 (22%) with amp.For MFS amp was observed in 5 out of 25 cases (20%).For 100 LMS cases, 5 (5%) had the amp.Among 59 DDLPS samples, 8 presented the amp (13%).Only 1 case in the SS group, out of 10 cases analyzed, exhibited amp.No amp was observed in the MPNST group (9 cases).Cohort 2 consisted of 2,922 samples across 38 cancers.The STS collection consisted of 34 cases, including 19 cases of DDLPS, with 16% (3/19) showing amp, and 15 cases of LMS, with an amp rate of 7%.Conclusions: Our findings underscore the need for further investigation of Nectin-4 in STS, including immunohistochemical analysis and clinical trials with ADCs such as Enfortumab-vedotin, emphasizing the potential of cutting-edge therapies to improve outcomes in sarcomas.