Identifying the distant metastasis genes by next-generation sequencing panel in nasopharyngeal carcinoma.

Abstract

e18547 Background: Even though local and regional controls have been substantially improved in nasopharyngeal carcinoma (NPC) in the contemporary era of intensity-modulated radiotherapy with extensive use of combined chemotherapy, the distant metastasis becomes the major cause of treatment failure and cancer-related death. To date, the genes contributed to metastasis of NPC is still unclear. The aim of this study was to identify the genes which lead to distant metastasis. Methods: A total of forty primary nonkeratinizing NPC patients were diagnosed at Shandong Cancer Hospital in this study. The formaldehyde-fixed paraffin embedded (FFPE) taken from primary sites or metastatic lymph nodes were performed next-generation sequencing (NGS) panel (Shanghai OrigiMed Co., Ltd.) to determine variated genes, such as single nucleotide variants (SNV), copy number variants (CNV) and rearrangement. These patients were followed up until Febr. 8, 2020. The genes related to distant metastasis were identified by logistic regression. Moreover, this study compared the frequency of mutated gene between our data and Catalog of Somatic Mutations in Cancer (COSMIC) database by the Chi-square test or Fisher’s exact test. Results: The study included 31 men and 9 women. The median age of the patients at diagnosis was 47 years (range 15–71 years). With the median follow-up of 10.6 months (range 16.8–72.3 months), 7 patients had distant metastasis and 1 undergone recurrent. Notably, EMSY and MCL1 variants were contributed to NPC distant metastasis (OR = 31, P = 0.049). The top eight SNV of genes in our study were CYLD, KMT2D, BAP1, EP300, TP53, ATM, NFKBIA and SPEN. When compared to COSMIC database, the mutant frequencies of CYLD, EP300 and BAP1 in our study were significantly higher than that of COSMIC database. However, the mutant frequencies of IDH2 and KMT2C were significantly lower than COSMIC database. Conclusions: This is the first study which suggests that EMSY and MCL1 variants were involved in the metastasis of NPC. The study identified 5 genes, which mutation frequency is significantly different from the COSMIC database. The study provided a molecular basis for a comprehensive understanding of, and exploring targeted therapies for nasopharyngeal carcinoma.