Science says

A report back on the latest medical and scientific studies from around the world.

Cancer

Powerful, tiny test detects tumours & suggests best treatment

Massachusetts General Hospital researchers have developed a powerful test that can identify tiny amounts of tumour cells floating in the blood of cancer patients.

Although the device is not yet ready for widespread use, the New England Journal of Medicine reports that it successfully identified migrating cancer cells in lung cancer patients and spotted important genetic quirks in those cells. The innovation could revolutionise treatment, especially for lung cancer.

The technology uses a scanner the size of a business card to analyse a patient's blood and can detect a single cancer cell among 1 billion healthy blood cells. Once those cells are captured, their genetic fingerprints can help determine the most effective drug for a patient whose cancer has already begun spreading, and show whether medication is still effective.

The test is now being used on patients whose cancer has already spread, but scientists hope in future the chip will be able to detect cancer's spread before secondary tumours become established.

The tiny device has 78 000 posts imbedded inside to trap cancer cells. Each of those posts is coated with a substance that acts like glue - glue designed to stick only to circulating tumour cells, known by the acronym CTC.

Already, the technology, known as the CTC-chip, has accurately identified bloodstream cancer cells in patients with advanced cancer of the lung, prostate, pancreas, breast, or colon.

Dr Daniel Haber, director of the Mass. General Hospital Cancer Center and senior study author says, "It's like a pinball machine - the blood has to flow through all of these columns to get to the other side. All the normal blood cells flow right through, but the very, very rare cancer cells stick to the columns."

The focus of the new study was on non-small-cell lung cancer. When the Mass. General team took blood from 27 lung cancer patients, the chip technology accurately detected circulating tumour cells in each patient.

And then they looked for crucial genetic mutations that would suggest particular treatments. By confirming with biopsied tissue, the scientists found that their test detected all the important genetic features they had sought.

The Mass. General technology needs to be tested in larger groups of patients before it can be used routinely, and scientists would like to speed up the device's ability to process samples - right now, it takes about 8 hours to run a blood sample and analyse it.

Source: Massachussetts General Hospital, July 2008, www.mgh.harvard.edu

Diabetes

High level of fetuin-A equals high risk for diabetes

According to a new study, having a higher than normal level of fetuin-A in the blood is linked to an increased risk for the development of diabetes.

The study's authors write: "Type 2 diabetes mellitus has become a global epidemic and the increased prevalence of obesity is a major contributing factor. However, diabetes does not develop in all obese individuals and there is a strong genetic contribution to risk. Despite significant recent advances, mechanisms responsible for individual differences in clinical phenotype remain largely unknown."

Previous studies have found a link between higher fetuin-A levels and insulin resistance, but the link with type 2 diabetes mellitus is unknown.

Dr Joachim Ix, of the University of California, San Diego, and colleagues conducted a study to examine whether higher fetuin-A levels are linked to occurrence of diabetes. The study included 406 people without diabetes at the start of the study, whose fetuin-A levels had been measured at baseline, and who had 6 years of follow-up. Diabetes developed in 135 cases.

Analysis showed a gradual increase in the incidence of diabetes with increased fetuin-A levels.

The group with the highest levels had more than double the incidence rate than the lowest third. The link was independent of patients' level of exercise, inflammatory biomarkers, and other commonly available measures of insulin resistance.

The study's authors conclude: "Future studies should evaluate whether the results may generalise to middle-aged individuals in whom the [diabetes] incidence rate is highest. If confirmed in future studies, fetuin-A may ultimately prove useful as a target for therapeutics, and its study may provide novel insights to glucose metabolism in humans."

Source: JAMA, 2008;300[2]:182-188, July 2008, http://pubs.ama-assn.org/media/2008j/0708.dtl#2

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