The method aims to help doctors calculate the chance of the cancer spreading or coming back. Present methods only serve as a rough guide at best and cannot predict what will happen to an individual woman with breast cancer. AdnaGen, a German biotech company, has developed this technology, which is being evaluated in clinical studies at The University of Texas M. D. Anderson Cancer Center in Houston,
The diagnostic tool is said to be able to spot one malignant cell in a typical blood sample. A typical sample is 5 millilitres and contains over 2.5 x 1010 cells.
As a biomarker for breast cancer metastasis, cancer cells circulating in the blood system have not been easy to detect and analyse because they are a "needle in the haystack" among the millions of cells in the bloodstream.
However, Winfried Albert, chief scientific officer of AdnaGen said that technology could detect the "needle" with a specificity of 97 per cent (only three "false" positive results in tests of 100 seemingly healthy people).
However, Albert said that AdnaGen's technology can detect the "needle" with a specificity of 97 per cent (only three "false" positive results in tests of 100 seemingly healthy people).
"Metastasis usually is detected by costly, cumbersome physical methods like computer tomography (CT)," said Albert.
"We have seen cases, where our test was positive, when there was still no clinical evidence. But at a careful second look through a CT scan, small metastatic lesions have been detected," he added.
Breast cancer is the second leading cause of cancer deaths in women today (after lung cancer) and is the most common cancer among women, excluding nonmelanoma skin cancers.
According to the World Health Organisation (WHO), more than 1.2m people will be diagnosed with breast cancer this year worldwide.
The American Cancer Society estimates that about 213,000 women in the US will be diagnosed with invasive breast cancer each year (Stages I-IV).
To produce its diagnostic tool, AdnaGen links an antibody-mix to magnetic beads. This antibody-mix is tailored to home in on specific molecular features, or antigens, of the respective cancer cells.
When exposed to a blood sample, the magnetic antibody-beads capture tumour cells possessing the specified antigens.
A magnetic particle concentrator then removes the tumour cells labelled with the magnetic beads, and the cells are then analysed to identify several gene products, including potential molecular targets for a specific drug.
Using this technology, AdnaGen discovered that the genetic signatures of the breast cancer and its metastases might differ, with the circulating tumour cells reflecting the gene expression profile of the metastases.
When metastasis has been diagnosed, treatments "usually has been chosen according to the features of the primary tumour, neglecting the fact that metastases can differ considerably from them," Albert noted.
AdnaGen, which is marketing its breast cancer assay (as well as assays for colon and prostate cancer) in Europe, is awaiting the results of a clinical trial before applying for FDA approval to make the test available in the US.
The research will be presented at the first international meeting on Molecular Diagnostics in Cancer Therapeutic Development, organised by the American Association for Cancer Research.
