Next-generation sequencing in advanced Chinese melanoma reveals therapeutic targets and prognostic biomarkers for immunotherapy

Limited studies have interrogated the genomic landscape of Chinese melanoma in which acral and mucosal melanoma are the mainstay. In this study, we carried out a retrospective analysis on 81 Chinese melanoma patients (15 acral, 25 mucosal and 41 cutaneous melanoma). With the identification of 1114 mutations spanning 248 genes, we summarized that the mutation spectrum varied significantly by subtypes. Acral melanoma and mucosal melanoma had significantly more CNVs. MYC amplification was one of the most commonly detected CNVs, other frequent CNVs in mucosal melanoma included NBN and KDR, which were associated with the poor survival of melanoma patients. A generally low TMB, with a median of only 5.1 mut/Mb, was observed in three groups including cutaneous melanoma. Additionally, over 50% variants in DNA damage repair pathway were detected in all three subtypes, most of which were HRD related genes. Patients with alterations of HRD related genes had a longer survival time after immunotherapy. This study revealed a molecular profiling of Chinese patients with advanced melanoma, and proposed the high variant rate in DDR pathway as a biomarker of immunotherapy, which might provide therapeutic targets and guidance in making clinical decision for different Chinese melanoma.