The importance of biomarker and molecular assays in the care of the patient with breast cancer continues to expand as more research is conducted, David J. Dabbs, MD, explains. The standard process at many institutions involves an examination of the breast cancer tissue using traditional pathology methodologies for grading, staging, and diagnosis. This information should be closely integrated with the hormone receptor status, HER2 status, and other data from pathological tests that may be performed, notes Dabbs.

In general, each laboratory should follow the ASCO/CAP guidelines for biomarker testing, specifically for HER2 and hormone receptor status, Dabbs suggests. These guidelines set recommendations for proper biomarker analysis and identification. Additionally, they provide recommendations on testing methodology.

Genomic profiling assays, such as Oncotype DX, MammaPrint, and Nanostring, are ideally utilized in tumors that are intermediate grade, Dabbs suggests. These tumors have a lot of variability that would benefit from the additional information gleaned from genomic assays.