OHSU Researchers Find Protein that may Signal the Spread of Breast Cancer

02/15/02    Portland, Ore.

Researchers at the Oregon Health & Science University Cancer Institute have found that a protein in human breast cancer indicates the disease has or will likely spread throughout the body. Currently a patient with a diagnosis of early or lymph node-negative breast cancer (isolated to one tumor) has about a 20 percent to 30 percent chance of metastasis, meaning the disease has spread beyond the breast. When the suspect protein was found to be present in human breast cancer tissue, the probability of metastasis tripled.

"In terms of prognostic markers in breast cancer, this finding is significant," said Gail Clinton, Ph.D., associate professor of biochemistry and molecular biology in the OHSU School of Medicine, and author of the study. "Since metastasis can kill breast cancer patients, this may prove to be a lifesaving indicator for many patients."

The study appears in the February issue of Clinical Cancer Research, published yesterday, and is featured on the journal¹s cover. Research was conducted by Clinton¹s lab in collaboration with Edward Keenan, Ph.D., professor of physiology and pharmacology in the OHSU School of Medicine, and with investigators in Spain directed by Jose Baselga, M.D.

Researchers have known that the HER-2 gene receptor is overexpressed in 20 percent to 30 percent of all breast cancer cases. However the HER-2 receptor does not predict metastasis and has had limited usefulness as a prognostic marker. The OHSU researchers have focused on a fragment of the receptor, called p95HER-2, which they believe has enhanced signaling activity in breast tumor cells and triggers the spread of the cancer early on.

"This is something that is worthy of more study and, if our theory holds true, we could see physicians using this marker as a test to predict the spread of breast cancer in patients in a few years," said Clinton.