Dozens of cancer studies may be thrown into doubt by the discovery that researchers inadvertently used the wrong type of cancer cells.

许多对于癌症的研究可能充满疑问，因为研究发现相关研究人员可能不经意间采用了错误的癌症细胞。

The samples of adenocarcinoma were widely supplied, the researchers say

The "cell lines细胞系", according to the Journal of the National Cancer Institute, were supplied as samples of oesophageal食管的 cancer.

However, tests show they contained other types of tumour¹, including lung and bowel²肠.

The Dutch researchers say this could put major trials of drugs in doubt.

Many experimental studies on cancer use laboratory-grown "cell-lines", meaning that dozens of studies may rely on cells originally taken from a single patient.

New drugs can be tested on these cells to see if they have an effect before they are tested on real patients.

The problem of "false" - or contaminated污染 - cell lines, is not a new one, and there have been calls for scientists to take more care verifying they have the right sort of cells before continuing with their experiments.

If not, they run the risk that their findings, positive or negative, may be misleading.

The latest example of the problem involved samples widely supplied as oesophageal adenocarcinoma癌腺，恶性肿瘤 cells, a particular type of cancer affecting the windpipe气管，嗓门.

In fact, they came from tumours³ of the lung, bowel and stomach, said researchers from the University Medical Centre in Rotterdam.

They wrote: "Experimental results based on these contaminated cell lines have led to ongoing⁴ clinical trials recruiting patients, to more than 100 scientific publications, and to at least three cancer research grants科研补助金 and 11 US patents - which emphasises the importance of our findings."

Widespread use of these cell lines could threaten the development of new treatments, they said.

In particular, use of the drug sorafenib索拉非尼 for some oesophageal cancer patients should be reconsidered, since the wrong cell line was used to assess its potential.

Specialist suppliers

However, writing in the same journal, Professor Robert Shoemaker of the National Cancer Institute in Maryland, said he suspected that a similar study using the right cell lines would support the use of sorafenib.

In the UK, one of the main funders of cancer studies, Cancer Research UK, has said that it uses DNA⁵ testing to check its cell lines.

The Health Protection Agency also operates an extensive cell culture collection and a spokesman said it urged scientists to, where necessary, pay for tests to check their cell lines.

He said: "The use of wrongly identified human cancer cell lines is a problem that was first recognised more than 20 years ago.

"We draw attention to this danger on our website, which includes an ever-expanding list of those cell lines known to be incorrectly identified, or cross-contaminated with a cell line of a different type.

"As a national culture collection we, together with other national collections, exhort劝诫，忠告 research scientists to always work with authenticated已验证 cell lines of known provenance出处，起源."