A breast cancer classifier that helps doctors tailor treatment to each patient has become available to patients around the country. As first reported in the 2009 Huntsman Cancer Institute (HCI) annual report, Philip Bernard, MD, HCI investigator and associate professor in the Department of Pathology at the University of Utah, led a research project to find a way to accurately identify the four major subtypes of breast cancer using the expression of a set of 50 genes (i.e. PAM50). The subtypes have different prognoses and respond differently to therapy.

The discovery of the PAM50 breast cancer signature was a collaborative effort between the HCI research group led by Bernard and investigators at the British Columbia Cancer Agency, University of North Carolina Lineberger Comprehensive Cancer Center, and Washington University in St. Louis.

In 2013, the PAM50 breast cancer signature received FDA approval and will launch the first quarter of 2014. The test is manufactured by NanoString Technologies, Inc., and is called the ProsignaTM breast cancer gene signature assay.

The ProsignaTM breast cancer test is indicated for postmenopausal women with node-negative (stage I or II) or node-positive (stage II), hormone receptor-positive (HR+) breast cancer. The gene expression data is combined with anatomic information (tumor size and node status) to tell what the patient’s risk of recurrence is at 10 years. Knowing the risk of recurrence can lead to better treatment choices from the start.

“The standard way to determine risk of recurrence is to look at histologic features, the tumor size and whether the cancer has left the primary site,” says Bernard. “Patients with larger tumors and positive node status would be given chemotherapy, but this test indicates that some can be spared this treatment.”

The PAM50 has shown to accurately identify which patients with breast cancer can be treated by endocrine therapy alone after surgery. Endocrine blockade therapy uses drugs to inhibit hormones like estrogen, which cause certain tumor types to grow. Endocrine therapy has fewer and milder side effects than chemotherapy.

“By being able to look at the molecular profile of these tumors, we can identify tumors that don’t need chemotherapy,” says Bernard. “We can personalize treatment based on the patient’s particular tumor profile.” In other words, there is no need to put those patients through the difficult side effects that come with chemotherapy such as anemia, nausea, nerve damage, mouth sores, dizziness, fatigue, swelling, skin rashes, and hair loss.

The test is currently offered by the national reference laboratory LabCorp, and will soon be offered at University of Utah’s ARUP Laboratories. Other labs across the country are expected to begin offering it as well.

“FDA approval was a big deal for us, because it meant we could offer the test at any lab,” says Bernard. “Now breast cancer patients in the United States and around the world can get a diagnosis quickly and receive the most appropriate treatment.”

Learn more about breast cancer risk factors, symptoms, and treatment as well as research from the Bernard Lab.