Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands ; Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
PLoS One. 2013 May 14;8(5):e62113. doi: 10.1371/journal.pone.0062113. Print 2013.
Cancer develops through a multistep process in which normal cells progress to malignant tumors via the evolution of their genomes as a result of the acquisition of mutations in cancer driver genes. The number, identity and mode of action of cancer driver genes, and how they contribute to tumor evolution is largely unknown. This study deployed the Mouse Mammary Tumor Virus (MMTV) as an insertional mutagen to find both the driver genes and the networks in which they function. Using deep insertion site sequencing we identified around 31000 retroviral integration sites in 604 MMTV-induced mammary tumors from mice with mammary gland-specific deletion of Trp53, Pten heterozygous knockout mice, or wildtype strains. We identified 18 known common integration sites (CISs) and 12 previously unknown CISs marking new candidate cancer genes. Members of the Wnt, Fgf, Fgfr, Rspo and Pdgfr gene families were commonly mutated in a mutually exclusive fashion. The sequence data we generated yielded also information on the clonality of insertions in individual tumors, allowing us to develop a data-driven model of MMTV-induced tumor development. Insertional mutations near Wnt and Fgf genes mark the earliest "initiating" events in MMTV induced tumorigenesis, whereas Fgfr genes are targeted later during tumor progression. Our data shows that insertional mutagenesis can be used to discover the mutational networks, the timing of mutations, and the genes that initiate and drive tumor evolution.
癌症是通过多步过程发展的，正常细胞通过获得癌症驱动基因中的突变，使基因组进化，从而进展为恶性肿瘤。癌症驱动基因的数量、身份和作用模式，以及它们如何促进肿瘤进化，在很大程度上是未知的。本研究利用小鼠乳腺肿瘤病毒（MMTV）作为插入诱变剂，寻找驱动基因及其作用网络。通过深度插入位点测序，我们在 604 个由 MMTV 诱导的乳腺肿瘤中鉴定了约 31000 个逆转录病毒整合位点，这些肿瘤来自乳腺特异性缺失 Trp53 的小鼠、Pten 杂合敲除小鼠或野生型小鼠。我们鉴定了 18 个已知的常见整合位点（CISs）和 12 个以前未知的 CISs，这些 CISs 标志着新的候选癌症基因。Wnt、Fgf、Fgfr、Rspo 和 Pdgfr 基因家族的成员以相互排斥的方式发生突变。我们生成的序列数据还提供了关于个体肿瘤中插入的克隆性的信息，使我们能够开发一种基于数据的 MMTV 诱导肿瘤发展模型。Wnt 和 Fgf 基因附近的插入突变标志着 MMTV 诱导肿瘤发生的最早的“启动”事件，而 Fgfr 基因则在肿瘤进展过程中晚期被靶向。我们的数据表明，插入诱变可以用于发现突变网络、突变的时间、以及启动和驱动肿瘤进化的基因。
