Cancer test

Researchers at Durham University have developed a test that uses light energy to measure the level of citrate in fluid samples from the prostate gland.

The technique could provide the basis of a rapid means of detecting prostate cancer in the future.

Almost a quarter of male cancers in the UK are diagnosed as prostate cancer and more than 10,000 men die from the disease each year.

Scientists, led by David Parker from Durham University’s chemistry department, have worked with partners from the University of Maryland in the US to develop the technique, which measures the wavelength of light as it is shone through diluted samples of body fluids.

The research team, funded by the North East Proof of Concept Fund and the EPSRC, believes that the technique can measure, with speed and accuracy, how citrate levels fall in the prostate gland as cancer develops.

It is claimed it also has the potential to find use for the diagnosis of other medical conditions associated with poor kidney-function.

‘Citrate provides a significant biomarker for disease that may provide a reliable method for screening and detecting prostate cancer and for the monitoring of people with the disease,’ said Parker.

‘This technique could form the basis of a simple screening procedure for prostate cancer that could be used in outpatient departments at local hospitals.’

Parker’s team has shone light into more than 100 different chemical structures to see how they function and respond to the presence of certain important bioactive species.

They have looked particularly closely at how citrate and lactate bind to luminescent structures within fluids.

Citrate and lactate are vital for the human body’s metabolism for normal function.

Citrate provides energy for cells and the amount found in the prostate varies considerably because of an enzyme called m-aconitase that transforms it.

This enzyme is sensitive to zinc and, in prostate cancer sufferers, zinc levels are depressed and the enzyme switches on again.

‘Citrate is formed in cell-metabolism processes that alter as cancers grow,’ said Leslie Costello from the University of Maryland.

‘The analysis of the citrate concentration of prostatic fluid can provide an accurate way to screen and diagnose prostate cancer.

‘Since citrate concentrations decrease markedly early in malignancy, this technique makes it possible to analyse what is happening quickly in the early and treatable stage of prostate cancer.

‘It shows much promise as a clinical tool.’

The new test requires only a microlitre of fluid and the sample can be easily measured in an optical instrument.

Using samples from male volunteers, the researchers have developed a portable instrument that can give results in three minutes.

The team’s challenge has been how to accurately measure changes in the amount of citrate or lactate in fluid samples, using the technique.

The early results are promising and the team intends to look at the analysis of other body fluids.

A possible way forward is to examine the citrate levels in seminal fluid samples, which are made up of 50 per cent prostate fluid.

The university has launched a spin-out company called FScan to develop the technique and to seek commercial backing.

The team has looked at 20 samples so far and verified the analysis in every case.

The next stage is to work with a local hospital and examine samples from 200 volunteers to see whether the first Durham results correlate.

‘It’s been a complex process to develop the technique but we’re very optimistic about it,’ said Parker.

‘Ultimately this could provide an accurate method of screening for prostate cancer in men that could be carried out in three-minutes once a biopsy has been obtained from the patient.’

The discovery follows the invention of a urine flow-meter in 2006 by Professor Douglas Newton of Durham University.

The UFlow Meter helps men to assess if they have a restricted rate of urine flow — one of the warning signs of prostate problems.

The establishment of FScan is part of the university’s aim to enhance the exploitation of the intellectual property generated by its research activities.

Tim Hammond, head of technology transfer at Durham University, said his group has worked with Prof Parker and his team to secure initial proof of concept funding through NorthStar Equity Investors and the North East Proof of Concept Fund and to establish FScan Limited as the vehicle to validate and commercialise the technology.