An automated assay for the quantitative measurement of the oncoprotein HER-2/neu in blood serum, which is associated with breast cancer
An automated assay for the quantitative measurement of the oncoprotein HER-2/neu in blood serum is now available from Bayer Diagnostics, a division of Bayer Healthcare, for use on the Advia Centaur automated immunoassay analyser.
The assay gained approval from the United States Food and Drug Administration (FDA) for use on the Advia Centaur earlier this year.
The assay is intended to be used as a complement to conventional tissue testing such as immunohistochemistry (IHC) or fluorescent in situ hybridisation (Fish), by providing a 'real time' picture of a patient's HER-2/neu levels via a simple blood test.
This not only enables oncologists to make better informed therapy management decisions, but also to monitor whether a particular therapy is having the desired effect on the disease.
Such benefits may also have a positive impact upon the total cost of patient care.
Studies have shown that in certain breast cancer patients, persistently rising HER-2/neu values may be associated with aggressive cancer and poor response to therapy, while decreasing HER-2/neu levels may be indicative of effective therapy (1).
Traditional HER-2/neu testing is generally limited to tissue from primary breast cancer and does not provide information regarding HER-2/neu status in women with recurrent metastatic breast cancer.
The introduction of HER-2/neu testing on the Advia Centaur offers a less invasive diagnostic tool and provides a current assessment of HER-2/neu status in patients with metastatic breast cancer whose initial HER-2/neu level is 15ng/ml or above.
Oncoproteins are biochemical compounds which play a direct role in the growth and spread of cancer tumours. HER-2/neu is an oncoprotein which is associated with cell proliferation in cases of metastatic breast cancer (ie, cancer which has spread throughout the body).
Measurement of HER-2/neu in a patient's blood assists doctors in monitoring the effectiveness of cancer treatment in a manner which is more convenient and less invasive than traditional tissue biopsies. Approximately 25% of breast cancers over-express HER-2/neu.
These tumours tend to grow faster and are generally more likely to recur than those that do not over-produce the oncoprotein.
Breast cancer affects almost four million women worldwide.
Approximately 50% of women with breast cancer develop cancer in other parts of their bodies within five years of diagnosis.
It is estimated that 50% - 70% of such patients have elevated levels of HER-2/neu in their blood.
The Advia Centaur immunoassay system offers the highest throughput of any immunoassay system on the market, enabling laboratories to meet the demands of ever-increasing workloads.
Designed for productivity, the analyser has a throughput of up to 240 tests per hour with on-board capacity for 180 samples.
Excellent testing sensitivity is achieved through the use of direct chemiluminescence technology which is applied across a comprehensive assay portfolio.
True random access operation allows any mix of assays to be run on the system at any time.
The Bayer HER-2/neu assay has been extensively evaluated on another automated analyser - the Bayer Immuno 1 - by Roy Sherwood, consultant clinical scientist at King's College Hospital in London.
"It simply is not practical to monitor the success of therapy by continuously taking biopsies of metastatic tumours", he says.
"However, availability of the serum assay allows you to monitor treatment efficacy and adjust dosage as appropriate, as well as being potentially diagnostic in cases where fresh tissue is not available. "This is particularly useful when there is a long time interval between the available primary tissue and the re-presentation of the patient.
"The assay performs very well on the Bayer Immuno 1 and I have been looking forward to trying it on the Advia Centaur", he continues.
"Some proteins can be notoriously difficult to measure when present in very low concentrations, but HER-2/neu is reported in terms of micrograms per litre as opposed to picograms and nanograms". Trials of the Bayer Advia Centaur HER-2/neu serum assay are currently underway in the laboratories at Kings College, Mater Public Hospital and Grampian University Hospital Trust.
