Comparison of risk classification between EndoPredict and MammaPrint in ER-positive/HER2-negative primary invasive breast cancer

PLoS One. 2017 Sep 8;12(9):e0183452. doi: 10.1371/journal.pone.0183452. eCollection 2017.

Abstract

Purpose: To compare the concordance in risk classification between the EndoPredict and the MammaPrint scores obtained for the same cancer samples on 40 estrogen-receptor positive/HER2-negative breast carcinomas.

Methods: Formalin-fixed, paraffin-embedded invasive breast carcinoma tissues that were previously analyzed with MammaPrint as part of routine care of the patients, and were classified as high-risk (20 patients) and low-risk (20 patients), were selected to be analyzed by the EndoPredict assay, a second generation gene expression test that combines expression of 8 genes (EP score) with two clinicopathological variables (tumor size and nodal status, EPclin score).

Results: The EP score classified 15 patients as low-risk and 25 patients as high-risk. EPclin re-classified 5 of the 25 EP high-risk patients into low-risk, resulting in a total of 20 high-risk and 20 low-risk tumors. EP score and MammaPrint score were significantly correlated (p = 0.008). Twelve of 20 samples classified as low-risk by MammaPrint were also low-risk by EP score (60%). 17 of 20 MammaPrint high-risk tumors were also high-risk by EP score. The overall concordance between EP score and MammaPrint was 72.5% (κ = 0.45, (95% CI, 0.182 to 0.718)). EPclin score also correlated with MammaPrint results (p = 0.004). Discrepancies between both tests occurred in 10 cases: 5 MammaPrint low-risk patients were classified as EPclin high-risk and 5 high-risk MammaPrint were classified as low-risk by EPclin and overall concordance of 75% (κ = 0.5, (95% CI, 0.232 to 0.768)).

Conclusions: This pilot study demonstrates a limited concordance between MammaPrint and EndoPredict. Differences in results could be explained by the inclusion of different gene sets in each platform, the use of different methodology, and the inclusion of clinicopathological parameters, such as tumor size and nodal status, in the EndoPredict test.

MeSH terms

  • Adipokines
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology*
  • Calcium-Binding Proteins / metabolism
  • Calmodulin / metabolism
  • Carrier Proteins / metabolism
  • Cytokine Receptor gp130 / metabolism
  • Extracellular Matrix Proteins / metabolism
  • Female
  • Glycoproteins / metabolism
  • Humans
  • Immunohistochemistry
  • In Vitro Techniques
  • Inhibitor of Apoptosis Proteins / metabolism
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Ki-67 Antigen / metabolism
  • Middle Aged
  • Oxidoreductases Acting on CH-CH Group Donors / metabolism
  • Proteins / metabolism
  • Receptor, ErbB-2 / metabolism*
  • Receptors, Estrogen / metabolism*
  • Receptors, Progesterone / metabolism
  • Ribosomal Proteins / metabolism
  • Survivin
  • Ubiquitin-Conjugating Enzymes / metabolism

Substances

  • AZGP1 protein, human
  • Adipokines
  • BIRC5 protein, human
  • CALM2 protein, human
  • Calcium-Binding Proteins
  • Calmodulin
  • Carrier Proteins
  • Extracellular Matrix Proteins
  • Glycoproteins
  • IL6ST protein, human
  • Inhibitor of Apoptosis Proteins
  • Intercellular Signaling Peptides and Proteins
  • Ki-67 Antigen
  • Proteins
  • RPL37A protein, human
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Ribosomal Proteins
  • STC2 protein, human
  • Survivin
  • matrix Gla protein
  • ornithine decarboxylase antizyme
  • Cytokine Receptor gp130
  • Oxidoreductases Acting on CH-CH Group Donors
  • 7-dehydrocholesterol reductase
  • UBE2C protein, human
  • Ubiquitin-Conjugating Enzymes
  • Receptor, ErbB-2

Grant support

The study was supported by the company Myriad Genetic España SLU. The funder provided support in the form of salaries for author AA, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of this author are articulated in the ‘author contributions’ section.