Abstract 2223: Distinct genomic features of cutaneous, acral and mucosal melanomas in a Chinese retrospective cohort

Abstract

Abstract Background: The incidence of each subtype of melanoma in different races and ethnicities is significant differences. Cutaneous melanomas dominate in the Caucasian population. In contrast, melanomas that occur in the Chinese population are mainly arising from non-cutaneous tissue (extremities and mucous). Here, we reported an analysis of genomic features in 97 acral, 52 cutaneous and 18 mucosal melanomas. Methods: Patients (pts) with melanoma were enrolled, and surgical tumor tissues were collected. Mutation profiling was performed by next-generation sequencing (NGS). Results: Comparing to cutaneous melanoma patients (Age 53±11.6), acral (Age 65±11.1, P<0.001) and mucosal (Age 64±9.7, P=0.01) melanomas occurred in older Chinese patients. Mutations were identified in 148 of melanoma patients (88.62%), including 85 acral (87.63%), 47 cutaneous (90.38%) and 16 mucosal (88.89%) melanomas. Mutations of BRAF (25/52) in cutaneous melanoma, NRAS in acral melanoma (22/97) and mucosal melanomas (5/18) were observed as the most commonly genetic variations in different subtype of melanoma, which always occurred mutual exclusivity. Furthermore, focal amplification of 11q13 (CCND1 and FGF3/4/19) was all abundant in acral melanoma (11.34%, 11/97), which was reported to affect the efficacy of immunotherapy. In total, occurrence of BRAF, NRAS, CDKN2A mutations and 11q13 amplification were significantly different in cutaneous and non-cutaneous melanomas, which suggested different pathogenesis. Conclusions: In summary, genomic characterization of melanomas may offer insights into tumorigenesis and identify potential therapeutic targets in this disease. Citation Format: Qiuyu Liu, Lingfei Kong, Weiran Wang, Danhua Wang, Tonghui Ma. Distinct genomic features of cutaneous, acral and mucosal melanomas in a Chinese retrospective cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2223.