来自上海交通大学、复旦大学和第二军医大学的研究人员，采用外显子组测序方法揭示出了肝母细胞瘤（hepatoblastoma）的一些新突变和癌基因，并证实它们与Wnt信号通路以及泛素连接酶复合体相关。这一研究发现已在国际著名肝脏疾病杂志Hepatology（最新影响因子12.003）在线发表。
上海交通大学的何祥火(Xianghuo He)教授、复旦大学的董岿然（Kuiran Dong）教授以及第二军医大学的王红阳（Hongyang Wang）院士是这篇论文的共同通讯作者。
为了鉴别出肝母细胞瘤的新突变，研究人员对6对肝母细胞瘤及匹配淋巴细胞进行了全外显子组测序。由此鉴别出了21个基因上的24种体细胞非同义突变，其中大多数的为新发突变，包括Wnt信号通路中CTNNB1 (G512V)和CAPRIN2 (R968H/S969C)基因的三个新突变。还发现了从前证实与泛素连接酶复合体相关的一些基因：SPOP、KLHL22、TRPC4AP和RNF169。
研究人员证实，在功能上CTNNB1 (G512V)和CAPRIN2 (R968H/S969C)均为功能获得性突变，在肝母细胞瘤中CAPRIN2 (R968H/S969C)激活了Wnt信号通路。这些研究结果表明在肝母细胞瘤中存在Wnt信号通路激活，通过在42个肝母细胞瘤肿瘤中对β-catenin进行免疫组化染色进一步证实了这一点。
随后，他们利用shRNA介导RNA干扰，评估了21种突变基因对于肝母细胞瘤细胞生存的影响。研究结果表明1种新的癌基因CAPRIN2和3种抑癌基因SPOP、OR5I1及CDC20B影响了肝母细胞瘤的细胞生长。并且，研究人员发现在肝母细胞瘤细胞中SPOP S119N是一种功能丧失性突变。他们最终证实SPOP可通过调控CDKN2B表达抑制肝母细胞瘤的细胞增殖。这些研究结果扩展了肝母细胞瘤的遗传变异图谱，阐明了Wnt和泛素信号通路调控异常在肝母细胞瘤的肿瘤形成中起着重要的作用。
外显子组测序 （Exome sequencing）是近年发展起来的一种利用序列捕获技术将全基因组外显子区域DNA捕捉并富集后进行高通量测序的基因组分析方法。是一种选择基因组的编码序列的高效策略，相对于基因组测序其成本较低。目前，外显子组测序已经在米勒综合症、歌舞伎综合症、重型颅脑畸形等孟德尔疾病的研究中得到成功应用。还有其它一些癌症和复杂性疾病也应用外显子组测序观察到高度相关的突变。
文章中外显子测序、SNP芯片以及后续的大部分数据分析均由晶能生物完成。
Abstract：
Hepatoblastoma (HB) is the most common primary liver tumor in children. Mutations in the β-catenin gene that leads to constitutive activation of Wnt pathway have been detected in a large proportion of HB tumors. To identify novel mutations in HB, we performed whole-exome sequencing of 6 paired HB tumors and their corresponding lymphocytes. This identified 24 somatic non-synonymous mutations in 21 genes, many of which were novel, including three novel mutations targeting the CTNNB1 (G512V) and CAPRIN2 (R968H/S969C) genes in the Wnt pathway, and genes previously shown to be involved in the ubiquitin ligase complex (SPOP,KLHL22, TRPC4AP and RNF169). Functionally, both the CTNNB1 (G512V) and CAPRIN2 (R968H/S969C) were observed to be gain-of-functional mutations, and theCAPRIN2 (R968H/S969C) was also shown to activate the Wnt pathway in HB cells. These findings suggested the activation of the Wnt pathway in HB, which was confirmed by immunohistochemical staining of the β-catenin in 42 HB tumors. We further used shRNA-mediated interference to assess the effect of 21 mutated genes on HB cell survival. The results suggested that 1 novel oncogene (CAPRIN2) and 3 tumor suppressors (SPOP, OR5I1 and CDC20B) influence HB cell growth. Moreover, we found that SPOP S119N is a loss-of-function mutation in HB cells. We finally demonstrated that one of the mechanisms by which SPOP inhibits HB cell proliferation is through regulating CDKN2B expression. Conclusion: these results extend the landscape of genetic alterations in HB and highlight the dysregulation of Wnt and ubiquitin pathways in HB tumorigenesis. (Hepatology 2014;)