Diagnostic test aims to determine which breast cancer patients may respond to treatment

Researcher estimates diagnostic test will be available in next 5 years

SAN DIEGO, Calif. – About 70% of breast cancer patients are estrogen-positive. Doctors can't predict which of them will respond to standard estrogen-blocking drugs. Forty percent of them won't, and their cancers grow, despite treatment.

Now, a researcher in California has found a diagnostic test that may tell doctors who will respond and who won't.

Helen Eckman was diagnosed with breast cancer when she was 42 and 49.

"Then, surprisingly, at 65, I was diagnosed with breast cancer that had gone and metastasized into my bones," Eckman said.

She's estrogen-positive, but there wasn't a reliable test to see if she'd respond to standard therapy.

Researcher Svasti Haricharan, Ph.D., assistant professor at the Department of Tumor Microenvironment and Cancer Immunology at Sanford Burnham Prebys, is working to change that now.

"We identified one particular protein that when it's lost or defective in women with breast cancer, they do not respond to standard care," Haricharan said.

That's about a third of ER positive women in Haricharan's study. She hopes to use an existing test that identifies the DNA defect in colorectal patients and a drug for metastatic breast cancer for treatment-resistant patients.

"The drug already is FDA approved. It's already in the clinic," Haricharan said. "The diagnostic test for this protein is already FDA approved and in the clinic. It's just a question of bringing them both together."

Existing approval means the test and treatment can get to patients more quickly. Helen's goldendoodle Dakota keeps things light while she presses on for herself, her two daughters and seven granddaughters.

"My hope is that even though I've gone through this journey painfully, but well, I would hope that my daughters and my granddaughters won't have to go through it at all," Eckman said.

The drug has worked in a clinical trial already.

Haricharan estimates that the diagnostic test will be available in the next five years.