《英文文献/摘要翻译》站在时间尽头2012

5、Mutational landscape of metastatic cancer

　　We analysed the mutational burden of each class of variant per cancer type based on the tissue of origin.
　　我们根据肿瘤原发组织分析了每种癌症类型变体的突变负荷（每百万碱基中被检测出的，体细胞基因编码错误、碱基替换、基因插入或缺失错误的总数。）

　　In line with previous studies on primary cancers, we found extensive variation in the mutational load of up to three orders of magnitude both within and across cancer types.
　　与以往关于原发癌的研究一致，我们发现在同种癌症和不同种癌症中，高达三个数量级的突变负荷存在广泛差别。

　　The median SNV counts per sample were highest in skin, predominantly consisting of melanoma and lung tumours, with tenfold higher SNV counts than sarcomas, neuroendo-crine tumours and mesotheliomas.
　　每个样本的单核苷酸变异数量中位数在外皮中最高，（肿瘤类型）主要包括黑色素瘤和肺肿瘤，它们的单核苷酸变异数量比肉瘤、神经内分泌肿瘤和间皮瘤高十倍。

　　SNVs were mapped to COSMIC (catalogue of somatic mutations in cancer) mutational signatures and were found to broadly match the patterns described in previous cancer cohorts per cancer type.
　　单核苷酸变异被映射（对应）到癌症体细胞突变查询表的突变特征，并被发现广泛匹配之前每种癌症类型队列描绘的模式。

　　However, several broad spectrum signatures such as S3, S8, S9 and S16 as well as some more specific signature (for example, S17 in specific tumour types) appear to be over-represented in our cohort.
　　然而，一些广谱特征，譬如基因组片段S3，S8，S9和S16，以及一些更具体的特征（譬如S17，特定肿瘤类型），似乎在我们的队列中有些过度表达了。

　　These observations may indicate enrichment of tumours that are deficient in specific DNA repair processes, increased hypermutation processes among advanced cancers, or reflect the mutagenic effects of previous treatments.
　　这些观察结果可能表明，在特定DNA的修复过程中并无丰富肿瘤，在晚期癌症中高突变过程的增加，或反映了以前治疗的诱变效应。

　　The variation for MNVs was even greater, with lung and skin tumours having five times the median MNV counts of any other tumour type.
　　多核苷酸的变异与变异之间有着更大差异，肺肿瘤和皮肤肿瘤的多核苷酸变异数量中位数，是其他所有肿瘤类型的五倍。

　　This can be explained by the well-known mutational effect of UV radiation and smoking mutational signatures, respectively.
　　这可以分别解释为【紫外线辐射与吸烟突变特征】众所周知的诱变效应。

　　Although only dinucleotide substitutions are typically reported as MNVs, 10.7% of the MNVs involve three nucleotides and 0.6% had four or more nucleotides affected.
　　虽然通常只有二核苷酸替代品被作为多核苷酸记录下来，但10.7%的多核苷酸涉及三种核苷酸，还有0.6%受到四种或更多种核苷酸影响。