Dr. Michael Gnant on the PAM50 Breast Cancer Intrinsic Subtypes

Michael Gnant, MD, professor of the Department of Surgery at the Medical University of Vienna in Vienna, Austria, discusses the four intrinsic subtypes of the PAM50 recurrence score test and a clinical trial comparing this test with OncotypeDX.

The PAM50 gene signature measures expression profiles for 50 genes and classifies tumors into four intrinsic subtypes (luminal A, luminal B, HER2-enriched, and basal-like). An algorithm is then used to combine the gene signature, intrinsic subtype, tumor size, and proliferation score.

This tool provides information that can be used to select an optimal treatment, based on breast cancer subtype. Additionally, it also reports a risk of recurrence (ROR) of score. The FDA cleared the Prosigna Breast Cancer Prognostic Gene Signature Assay, which incorporates the PAM50 test, for marketing in the United States under its 510(k) program on September 9, 2013.

A study compared the PAM50 assay with the OncotypeDX 21-gene assay. According to the study that was published in the Journal of Clinical Oncology, researchers reported that the ROR score obtained via the PAM50 assay provided more prognostic information than the recurrence score (RS) obtained by the OncotypeDX in patients with estrogen receptor (ER)-positive, node-negative early breast cancer, Gnant explains.