Comparison of Molecular Subtyping with BluePrint, MammaPrint, and TargetPrint to Local Clinical Subtyping in Breast Cancer Patients

Publication Name: Annals of Surgical Oncology

Author(s): Bichlien Nguyen, Pino G. Cusumano, Kenneth Deck, Deborah Kerlin, Agustin A. Garcia, Julie L. Barone, Edgardo Rivera, Katharine Yao, Femke A. de Snoo, Jeroen van den Akker, Lisette Stork-Sloots, Daniele Generali

Purpose:

To compare breast cancer subtyping with the three centrally assessed microarray-based assays BluePrint, MammaPrint, and TargetPrint with locally assessed clinical subtyping using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).

Methods:

BluePrint, MammaPrint, and TargetPrint were all performed on fresh tumor samples. Microarray analysis was performed at Agendia Laboratories, blinded for clinical and pathological data. IHC/FISH assessments were performed according to local practice at each institution; estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) assessments were performed on 132 samples, and Ki-67 on 79 samples.

Results:

The concordance between BluePrint and IHC/FISH subtyping was 94 % for the Luminal-type, 95 % for the HER2-type, and 94 % for the Basal-type subgroups. The concordance of BluePrint with subtyping using mRNA single gene readout (TargetPrint) was 96 % for the Luminal-type, 97 % for the HER2-type, and 98 % for the Basal-type subgroups. The concordance for substratification into Luminal A and B using MammaPrint and Ki-67 was 68 %. The concordance between TargetPrint and IHC/FISH was 97 % for ER, 80 % for PR, and 95 % for HER2.

Conclusions:

The implementation of multigene assays such as TargetPrint, BluePrint, and MammaPrint may improve the clinical management of breast cancer patients. High discordance between Luminal A and B substratification based on MammaPrint versus locally assessed Ki-67 or grade indicates that chemotherapy decisions should not be based on the basis of Ki-67 readout or tumor grade alone. TargetPrint serves as a second opinion for those local pathology settings where high-quality standardization is harder to maintain.

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