Diverse Distribution and Gene Expression on the 21-Gene Recurrence Assay in Breast Cancer Patients with Locoregional Recurrence Versus Distant Metastasis

Abstract

Background

It remains uncertain whether the 21-gene recurrence score (RS) of a primary tumor has selective prognostic value for locoregional recurrence (LRR) or distant metastasis (DM). The current study aimed to compare the distribution and single-gene expression on the RS panel in breast cancer patients with LRR versus DM.

Methods

Consecutive early breast cancer patients who had been operated on at the Comprehensive Breast Health Center, Ruijin Hospital from January 2009 to December 2016 were retrospectively reviewed. Patients were divided into LRR, DM, and no-recurrence groups according to the first reported recurrent event. Comparison and subgroup analysis of 21-gene RS, RS category, and single-gene expression on the RS panel were conducted among patients with different recurrence status.

Results

A total of 1,287 patients were included, with median follow-up of 61.5 months, and 27, 47, and 1,213 patients were classified as LRR, DM, and no recurrence groups, respectively. RS was significantly diversely distributed among the three groups (P<0.001). No-recurrence patients (median 22) presented much lower RS than LRR (median 39, P<0.001) and DM (median 30, P<0.001) patients. LRR patients had lower PR (P<0.001), BCL2 (P=0.010), and CEGP1 (P<0.001) expression, and DM patients had higher STMY3 (P=0.019) expression than no-recurrence patients. Moreover, CEGP1 expression was significantly lower in the LRR group than the DM one (P=0.028).

Conclusion

RS was differently distributed between recurrent and nonrecurrent patients. PR, BCL2, CEGP1, and STMY3 expression was associated with LRR and DM, while CEGP1 was lower in the LRR group than DM patients, warranting further clinical evaluation.

Keywords:

• breast cancer
• 21-gene recurrence assay
• gene expression
• locoregional recurrence
• distant metastasis

Acknowledgments

The authors would like to thank the assistance of Ms Yidong Du in inputting SJTU-BCDB and Dr Yitian Xiao from the University of California, Davis in language polishing.

Abbreviations

RS, recurrence score; LRR, locoregional recurrence; DM, distant metastasis.

Data Sharing Statement

All data of this article were retrieved from the Shanghai Jiao Tong University Breast Cancer Database (SJTU-BCDB), and are available on request to the corresponding author, Professor Xiaosong Chen.

Ethics Approval

This study was reviewed and approved by the independent ethical committees of Ruijin Hospital, Shanghai Jiaotong University School of Medicine. All procedures involving human participants were consistent with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.

Consent for Publication

All authors gave consent for publication.

Disclosure

The authors declare no competing interests.