Al-Hebshi Nezar Noor, Li Shiyong, Nasher Akram Thabet, El-Setouhy Maged, Alsanosi Rashad, Blancato Jan, Loffredo Christopher
Department of Preventive Dentistry, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia.
Department of Oncology and Pharmacogenomics, Beijing Genome Institute (BGI), Shenzhen, Republic of China.
Int J Cancer. 2016 Jul 15;139(2):363-72. doi: 10.1002/ijc.30068. Epub 2016 Mar 18.
The study sought to identify genetic aberrations driving oral squamous cell carcinoma (OSCC) development among users of shammah, an Arabian preparation of smokeless tobacco. Twenty archival OSCC samples, 15 of which with a history of shammah exposure, were whole-exome sequenced at an average depth of 127×. Somatic mutations were identified using a novel, matched controls-independent filtration algorithm. CODEX and Exomedepth coupled with a novel, Database of Genomic Variant-based filter were employed to call somatic gene-copy number variations. Significantly mutated genes were identified with Oncodrive FM and the Youn and Simon's method. Candidate driver genes were nominated based on Gene Set Enrichment Analysis. The observed mutational spectrum was similar to that reported by the TCGA project. In addition to confirming known genes of OSCC (TP53, CDKNA2, CASP8, PIK3CA, HRAS, FAT1, TP63, CCND1 and FADD) the analysis identified several candidate novel driver events including mutations of NOTCH3, CSMD3, CRB1, CLTCL1, OSMR and TRPM2, amplification of the proto-oncogenes FOSL1, RELA, TRAF6, MDM2, FRS2 and BAG1, and deletion of the recently described tumor suppressor SMARCC1. Analysis also revealed significantly altered pathways not previously implicated in OSCC including Oncostatin-M signalling pathway, AP-1 and C-MYB transcription networks and endocytosis. There was a trend for higher number of mutations, amplifications and driver events in samples with history of shammah exposure particularly those that tested EBV positive, suggesting an interaction between tobacco exposure and EBV. The work provides further evidence for the genetic heterogeneity of oral cancer and suggests shammah-associated OSCC is characterized by extensive amplification of oncogenes.
该研究旨在确定导致阿拉伯无烟烟草制品沙玛使用者发生口腔鳞状细胞癌(OSCC)的基因畸变。对20份存档的OSCC样本进行了全外显子测序,平均深度为127倍,其中15份有沙玛接触史。使用一种新型的、与匹配对照无关的过滤算法来识别体细胞突变。采用CODEX和Exomedepth并结合基于基因组变异数据库的新型过滤器来检测体细胞基因拷贝数变异。使用Oncodrive FM和Youn与Simon的方法来识别显著突变的基因。基于基因集富集分析提名候选驱动基因。观察到的突变谱与TCGA项目报告的相似。除了确认OSCC的已知基因(TP53、CDKNA2、CASP8、PIK3CA、HRAS、FAT1、TP63、CCND1和FADD)外,分析还确定了几个候选的新型驱动事件,包括NOTCH3、CSMD3、CRB1、CLTCL1、OSMR和TRPM2的突变,原癌基因FOSL1、RELA、TRAF6、MDM2、FRS2和BAG1的扩增,以及最近描述的肿瘤抑制因子SMARCC1的缺失。分析还揭示了OSCC中以前未涉及的显著改变的信号通路,包括抑瘤素-M信号通路、AP-1和C-MYB转录网络以及内吞作用。有沙玛接触史的样本,特别是那些EBV检测呈阳性的样本,其突变、扩增和驱动事件的数量有增加的趋势,这表明烟草接触与EBV之间存在相互作用。这项工作为口腔癌的基因异质性提供了进一步的证据,并表明与沙玛相关的OSCC的特征是癌基因的广泛扩增。