| Background Melanoma is a malignancy of pigment-producing cells called melanocytes,which can be found throughout the body(including in the skin,iris and rectum).In 2011,the American Society of Clinical Oncology(ASCO)classified malignant melanoma into four types: acral,mucosal,chronic sun damage,and non-chronic sun damage(including unidentified primary).Cutaneous melanoma occurs mainly in populations with fair skin and accounts for 75% of cutaneous cancer mortality,with a global incidence of 15-25/100,000,whereas populations from Africa and Asia with more deeply pigmented skin mainly develop acral and mucosal melanoma.The most common malignant melanoma in China is acral and mucosal melanoma.Mucosal melanomas can arise from any mucosal tissue where melanocytes are present,but it most typically affects the mucosal epithelium of the respiratory,alimentary and genitourinary tracts.Mucosal melanoma is an extremely rare subtype of melanoma,accounting for 0.03% of all cancer diagnoses and 1.3% of melanoma.Mucosal melanoma is more aggressive and has a poorer prognosis than cutaneous melanoma,no matter which stage of the disease is diagnosed.Due to its rarity,it is a disease that is rarely described and rarely studied,so it lacks a range of research data on its epidemiology,etiology and pathogenesis,as well as supporting systems for accurate diagnosis and treatment.Therefore,research on the pathogenesis of mucosal malignant melanoma is necessary.As a special subtype of melanoma,the genetic mechanism of mucosal melanoma is significantly different from that of cutaneous melanoma.Mutations such as the BRAF gene are common in cutaneous melanoma,while BRAF mutations are rare in mucosal melanoma.From a therapeutic point of view,mucosal melanoma has a more prominent incidence of high activating mutations and/or amplification in KIT oncogenes.With the rapid development of high-throughput genotyping technology and the continuous reduction of typing costs,advances in sequencing technology can effectively identify susceptible genes for complex diseases.Melanoma genetics research has made great progress,due to its low incidence,and sample collection is difficult,compared to many reported genetic changes associated with cutaneous melanoma the genetic study of mucosal melanoma is relatively rare.Object Mucosal melanoma is a special malignant melanoma that is significantly different from cutaneous melanoma in epidemiology,etiology,pathogenesis and treatment.However,as a subtype of melanoma,its pathogenesis and melanoma still have an unavoidable connection,which has certain commonalities.We designed a target sequencing for 100 melanoma related susceptibility genes to detected the most likely susceptibility genes associated with mucosal melanoma,and narrowed the range of candidate genes associated with mucosal melanoma.Further analysis of data to further subdivide these susceptibility genes to the different direction of research on mucosal melanoma,which could provide direction and help for other areas of research such as: mechanical pathology and personalized precision treatment.Methods According to the Agilent website,the targeted sequencing probes was designed for 100 specific genes,and the DNA of 39 mucosal melanoma samples were extracted and sequenced by Illumina HiSeq4000 platform.After preliminary data quality control,the Burrows-Wheeler Aligner(BWA)software was used to compare the sequencing sequence with the human reference genome sequence.SAMtools are used to process single nucleotide variations(SNVs)and insertions and deletions(InDels),and ANNOVAR is used for data annotation.Missense mutations and driver gene screening were performed on the identified mucosal melanoma related susceptibility genes.Subsequently,in order to select the candidate genes with the most potential research and clinical application value,pathway enrichment,targeted drug gene therapy,protein interaction network and other comprehensive analysis were conducted on the found mucosal melanoma genes.Results Through somatic cell mutation analysis and driver gene screening of the sequenced results,49 known driver genes have missense mutations in mucosal melanoma were detected in this study,accounting 64% of the total samples(25/39).Including some driver genes not proved associated with mucosal melanoma,such as: SETD2,mutation accounted for 20%(5/25);MECOM/ ERCC3,mutation accounted for 16%(4/25);ERBB2/ERCC5,mutation 12%(3/25)and so on.Enrichment analysis and gene protein-protein interaction enrichment analysis suggest that the ERCC gene family which involved in the nucleic acid cleavage repair signaling pathway and the ERBB gene family which involved in the epidermal growth factor receptor signaling pathway plays an important role in the pathological progress in mucosal melanoma.Finally,the 49 genes were integrated with the major drug databases FDA,PharmGKB,DrugBank and My Cancer Genome to screen out 30 targeted drug candidate genes.Conclusions This study is the first in-depth targeted sequencing study on mucosal melanoma in Chinese han population.The results of the study confirm that although mucosal melanoma is specific compared with other types of melanoma,some of the susceptibility genes in its pathogenesis are still coincident.In this study,the candidate genes and their missense mutation points obtained through the screening of functional driver genes and the comprehensive analysis of pathway enrichment can be used as the basis for the functional study of mucosal melanoma.ERBB4 gene was detected to have ERBB4 mutation in the mucosal melanoma of han Chinese population for the first time.The mutation of SF3B1 may not exist in oral mucosal melanoma.For other CBL,MAP2K2,MAP2K1,RAF1 and other reported susceptibility genes related to cutaneous melanoma,it is the first time to detect missense mutations in mucosal melanoma.This study also summarized and expanded the relevant targeted drugs for driver gene mutations detected in mucosal melanoma,providing new ideas and directions for the accurate treatment of clinical targeted drugs for mucosal melanoma. |
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