Buechler SA, Gökmen-Polar Y, Badve SS. EarlyR: A Robust Gene Expression Signature for Predicting Outcomes of Estrogen Receptor-Positive Breast Cancer.
Clin Breast Cancer 2018;
19:17-26.e8. [PMID:
30097312 DOI:
10.1016/j.clbc.2018.07.011]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 05/01/2018] [Accepted: 07/09/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION
Early stage estrogen receptor (ER)-positive breast cancer may be treated with chemotherapy in addition to hormone therapy. Currently available molecular signatures assess the risk of recurrence and the benefit of chemotherapy; however, these tests may have large intermediate risk groups, limiting their usefulness.
METHODS
The EarlyR prognostic score was developed using integrative analysis of microarray data sets and formalin-fixed, paraffin-embedded-based quantitative real-time PCR assay and validated in Affymetrix data sets and METABRIC cohort using Cox proportional hazards models and Kaplan-Meier survival analysis. Concordance index was used to measure the probability of prognostic score agreement with outcome.
RESULTS
The EarlyR score and categorical risk strata (EarlyR-Low, EarlyR-Int, EarlyR-High) derived from expression of ESPL1, MKI67, SPAG5, PLK1 and PGR was prognostic of 8-year distant recurrence-free interval in Affymetrix (categorical P = 3.5 × 10-14; continuous P = 8.8 × 10-15) and METABRIC (categorical P < 2.2 × 10-16; continuous P < 10-16) data sets of ER+ breast cancer. Similar results were observed for the breast cancer-free interval end point. At most 13% of patients were intermediate risk and at least 66% patients were low risk in both ER+ cohorts. The EarlyR score was significantly prognostic (distant recurrence-free interval; P < .001) in both lymph node-negative and lymph node-positive patients and was independent from clinical factors. EarlyR and surrogates of current molecular signatures were comparable in prognostic significance by concordance index.
CONCLUSION
The 5-gene EarlyR score is a robust prognostic assay that identified significantly fewer patients as intermediate risk and more as low risk than currently available assays. Further validation of the assay in clinical trial-derived cohorts is ongoing.
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