Dr. Whitworth on the Importance of Additional HER2 Subtyping

Pat Whitworth, MD, medical oncologist, Nashville Breast Center, discusses the prospective neoadjuvant NBRST study, which looked at BluePrint functional subtyping versus conventional immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in breast tumors.

The BluePrint 80-gene functional molecular subtype assay is based on mRNA expression associated with intact translation to protein.

The study found that half of the tumors that would normally be identified as HER2-positive by FISH and estrogen receptor (ER)-positive by IHC were classified as luminal A subtype by BluePrint functional subtyping.

(CR)

This group of patients, when treated with chemotherapy and traztumab, had a very low complete response rate, says Whitworth. However, when pertuzumab was added, the CR rate jumped dramatically, he says.

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