英國科學家找到了“急性癌癥”的形成原因：細胞內的染色體發生“爆炸”破壞了DNA，從而讓人有可能在短時間內患上癌癥。相關論文發表于Cell。

傳統理論認為癌癥是人體經歷成千上萬次的細胞突變后，慢慢演化的結果。但英國著名的疾病研究機構桑格研究所的新發現推翻了這種看法。這暗示了不管人們怎么努力保持身體健康，也不能保證命運不會拿他們開玩笑。同時還說明了為什么有些人在體檢時根本沒發現癌癥痕跡，但數月后突然就被診斷患上這種疾病了。

桑格學院的科學家是通過研究750個腫瘤的遺傳缺陷后得出以上結論的。其中大部分的案例都與傳統理論相符，染色體的損壞是常年累積的結果。然而，其中至少有1/40的腫瘤不符合“標準模式”，有的染色體似乎是在一夜之間遭到破壞的。

參與此項研究的坎貝爾博士稱：“測驗結果太讓我們驚訝了。在一個細胞里面，染色體經過一次或者是多次爆炸成為碎片。如果這個細胞開始笨拙地修補，把碎片雜亂的縫合起來，這樣就破壞了原來的DNA結構，為癌癥的快速形成提供了條件。”

坎貝爾博士表示：“這個細胞應該說‘好吧，我放棄’，而不是像對待昂貴的瓷器一樣，把染色體拼接回去。細胞試圖修復一個不可修復的東西，最后造出一個災難性的、能讓癌癥更快形成的基因組。”

這種“急性癌癥”在骨癌里面特別常見，大概1/4的患者身上都能看到明顯的染色體受損特征模式。科學家目前還不能肯定是什么引起了這種染色體“爆炸”，但有嫌疑的罪魁禍首包括X光和曬傷。坎貝爾博士稱：“如果我們能了解根本的病因，或許就可以防止患上這種癌癥。”

推薦原文出處：

Cell  doi:10.1016/j.cell.2010.11.055

Massive Genomic Rearrangement Acquired in a Single Catastrophic Event during Cancer Development

Philip J. Stephens, Chris D. Greenman, Beiyuan Fu, Fengtang Yang, Graham R. Bignell, Laura J. Mudie, Erin D. Pleasance, King Wai Lau, David Beare, Lucy A. Stebbings, Stuart McLaren, Meng-Lay Lin, David J. McBride, Ignacio Varela, Serena Nik-Zainal, Catherine Leroy, Mingming Jia, Andrew Menzies, Adam P. Butler, Jon W. Teague, Michael A. Quail, John Burton, Harold Swerdlow, Nigel P. Carter, Laura A. Morsberger, Christine Iacobuzio-Donahue, George A. Follows, Anthony R. Green, Adrienne M. Flanagan, Michael R. Stratton, P. Andrew Futreal, Peter J. Campbell

Highlights

2%–3% cancers show 10–100 s of rearrangements localized to specific genomic regions

Genomic features imply chromosome breaks occur in one-off crisis (“chromothripsis”)

Found across all tumor types, especially common in bone cancers (up to 25%)

Can generate several genomic lesions with potential to drive cancer in single event

Summary

Cancer is driven by somatically acquired point mutations and chromosomal rearrangements, conventionally thought to accumulate gradually over time. Using next-generation sequencing, we characterize a phenomenon, which we term chromothripsis, whereby tens to hundreds of genomic rearrangements occur in a one-off cellular crisis. Rearrangements involving one or a few chromosomes crisscross back and forth across involved regions, generating frequent oscillations between two copy number states. These genomic hallmarks are highly improbable if rearrangements accumulate over time and instead imply that nearly all occur during a single cellular catastrophe. The stamp of chromothripsis can be seen in at least 2%–3% of all cancers, across many subtypes, and is present in ～25% of bone cancers. We find that one, or indeed more than one, cancer-causing lesion can emerge out of the genomic crisis. This phenomenon has important implications for the origins of genomic remodeling and temporal emergence of cancer.

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