血檢或可識別腫瘤位置

A blood test for cancer can now show where in the body a tumour is growing, without the need for a painful biopsy.

一種癌症的血液檢測方法可以測出腫瘤在體內生長的位置，而不需要進行活組織檢測。

'Liquid biopsies' are hoped to revolutionise cancer treatment, by identifying people with slow-growing tumours and those most in danger. They work by detecting the DNA released by dying tumour cells.

人們希望通過“血液活檢”發現人體內的慢性腫瘤和最危險的腫瘤，從而徹底改變癌症的治療方式。其原理是檢測死亡腫瘤細胞釋放的DNA。

Now, for the first time, US scientists can also pinpoint the part of the body affected.

現在，美國科學家還首次實現精準定位患病的部位。

That is because the normal cells killed off by cancer also release DNA into the bloodstream, which has its own unique signature.

這是因爲被癌症殺死的正常細胞也會將DNA釋放到血液中，這些DNA有其獨特的特徵。

A team from the University of California San Diego have found the DNA patterns for 10 different types of tissue, including from the liver, lung and kidneys.

加利福尼亞大學聖地亞哥分校的一個研究小組發現了肝、肺、腎等10種不同人體組織的DNA模式。

It means cancer patients who have symptoms shared across different types of cancer, such as bloating or sudden weight loss, could in future be diagnosed quickly and easily without needing a biopsy to remove part of an organ for testing.

這意味着未來人們可以簡單快速確診出現腹脹、體重驟減等癌症一般症狀的病患，而無需切除器官的一部分用來進行活組織檢測。

Dr Catherine Pickworth, Cancer Research UK's science information officer, said: 'A biopsy can be invasive and unpleasant to go through, while any operation with an anaesthetic is risky.

英國癌症研究所科學信息主任凱瑟琳?皮克沃思博士稱：“開刀進行活組織檢測是有創的，而任何使用麻醉劑的手術都是有風險的。

This is potentially safer if it can be effective, which is why people are focusing on liquid biopsies.

如果血液檢測有效，那麼這種方法會更安全，這也正是人們關注血液活檢的原因。

Finding new ways to detect and treat cancer at an early stage is vital to help more people survive the disease. Looking for the DNA of cancer cells in the blood is an exciting idea, and this encouraging new approach might help reveal the location of tumours. '

尋找在初期檢測和治療癌症的新方法對拯救更多的癌症患者至關重要。尋找血液中的癌細胞DNA是一個激動人心的想法，而且這種新方法可能有助於揭示腫瘤的位置。”

The US researchers, whose study is published in Nature Genetics, analysed samples of tumours and blood samples from cancer patients to find markers for different organs in the blood.

美國研究人員分析了癌症患者的腫瘤樣本和血液樣本，從而找出血液中不同器官的標記。他們將研究成果發表在了《自然遺傳學》雜誌上。

They created a DNA database for the liver, intestine, colon, lung, brain, kidney, pancreas, spleen, stomach and blood.

研究人員創造了一個肝臟、腸道、結腸、肺、腦、腎、胰腺、脾、胃以及血液的DNA數據庫。

Now the bioengineers know the normal cells, killed off when tumour cells compete with them for space and nutrients, also release a DNA signature, called CpG methylation haplotypes.

現在，這些生物工程師們發現在與腫瘤細胞爭奪空間及營養物質時被殺死的正常細胞也釋放一種DNA信號，叫做CpG甲基化單體。

They were able to test which organ they came from by checking their diagnoses back against the cancer patients.

他們可以通過對比癌症患者之前的診斷檢測出這些細胞來自哪個器官。

The researchers screened blood samples from individuals with and without tumours, looking for signals of the cancer markers and the tissue-specific methylation patterns.

研究人員通過檢測患有癌症和健康的個體的血液樣本，尋找腫瘤標誌物的信號以及組織特異的甲基化模式。

The test works like a dual authentication process, with the combination of both signals required to assign a positive match.

這個測試就像是一個雙重認證過程，兩種信號的組合需要正向匹配。

The author added: 'This a proof of concept. To move this research to the clinical stage, we need to work with oncologists to further optimise and refine this method.'

研究作者稱：“這還是概念驗證。要將該研究應用於臨牀，我們需要和腫瘤專家進一步完善和優化這個方法。”