PNNL improves tests to detect breast cancer

RICHLAND -- Research at Pacific Northwest National Laboratory may lead to more accurate early detection of breast cancer.

Scientists at the Department of Energy laboratory in Richland have refined blood tests that could indicate whether abnormalities found in mammograms are likely to be cancerous or benign.

Although early detection of breast cancer saves lives, screening for breast cancer also produces false alarms that are stressful for patients and may require surgery or other invasive or expensive procedures to determine there is no cancer.

But PNNL researchers showed in a small study that a panel of proteins shed by breast cancer can easily be detected using diagnostic tools already in clinics and can indicate whether a lump is likely to be cancerous or benign.

"We really want to expand the work to verify our findings," PNNL biologist Richard Zangar, who led the study, said in a statement.

Earlier research had used a simple clinical blood test to detect proteins, called biomarkers, shed by cancerous tissues.

But in studies the biomarkers had almost as many false positives as mammograms.

PNNL researchers took the idea a step further, after wondering if looking for biomarkers specific for different subtypes of breast cancer would improve the odds of getting the diagnosis right.

Breast cancer exists as several subtypes, with each subtype having different characteristics.

For example, breast cancers that produce proteins called estrogen receptors differ from those that do not, and each responds to different treatments.

PNNL and Duke University researchers worked together, picking 23 biomarkers and measuring them using a test similar to ones found in clinics.

The team compared proteins in blood from women who had previously had lumps determined to be noncancerous with proteins in blood from four groups of about 20 women each for four subtypes of cancer.

The biomarker panel for each subtype was significantly better at distinguishing between breast cancer and benign lumps than mammograms or single biomarkers.

"Perhaps researchers haven't found good biomarkers because they've been treating the different subtypes as a single disease, but they actually represent unique diseases that are associated with different biomarkers," Zangar said.

The PNNL study also hints about the underlying biology of breast cancer.

Four of the biomarkers are proteins involved in normal breast development that turn on and off at different times during growth.

The fact that these proteins show up in different ways, depending on the subtype of breast cancer, might provide clues about what goes wrong when breast tissue turns cancerous, according to PNNL.

The team is seeking money to repeat the biomarker study in larger groups of women and to follow the volunteers for several years.