MammaPrint versus EndoPredict: Poor correlation in disease recurrence risk classification of hormone receptor positive breast cancer

PLoS One. 2017 Aug 29;12(8):e0183458. doi: 10.1371/journal.pone.0183458. eCollection 2017.


Introduction: Correct risk assessment of disease recurrence in patients with early breast cancer is critically important to detect patients who may be spared adjuvant chemotherapy. In clinical practice this is increasingly done based on the results of gene expression assays. In the present study we compared the concordance of the 70-gene signature MammaPrint (MP) with the 12 gene assay EndoPredict (EP).

Methods: Representative tissue of 48 primary tumours was analysed with the MP during routine diagnostic purposes. Corresponding formalin-fixed, paraffin-embedded tissue was thereafter analysed by the EP test. Risk categories of both tests were compared.

Results: 41 of 48 tumours could be directly compared by both tests. Of the 17 MP low risk cases, only 9 were considered low risk by EP (53% agreement) and of the 24 MP high risk cases, 18 were high risk by EP (75% agreement). Discrepancies occurred in 14 of 41 cases (34.1%). There was only a weak and non-significant correlation between the MP and EP test with an overall concordance of only 66%. The original therapeutic recommendation was based on the MP and would have been changed in 38% of the patients following EP test results. 4 patients developed distant metastases. The respective tumours of these patients were all classified as high risk by the EP, but only 3 were classified as high risk by the MP.

Conclusion: Both tests resulted in different treatment recommendations for a significant proportion of patients and cannot be used interchangeably. The results underscore the urgent need for further comparative analyses of multi-genomic tests to avoid misclassification of disease recurrence risk in breast cancer patients.

MeSH terms

  • Adult
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Female
  • Gene Expression Profiling / methods*
  • Humans
  • Middle Aged
  • Neoplasm Recurrence, Local / genetics*
  • Neoplasm Recurrence, Local / pathology
  • Prognosis
  • Risk Assessment / methods
  • Risk Factors

Grants and funding

The analyses for the EndoPredict test were carried out blinded to the outcome data and the MammaPrint results in the lab of the manufacturer Sividon Diagnostics in Germany. All reagents for the EndoPredict analysis were provided by Sividon Diagnostics. In addition to that the authors received no specific funding for this work. Sividon Diagnostics had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.