Concordance of the 21-gene assay between core needle biopsy and resection specimens in early breast cancer patients

Abstract

Background Adjuvant therapy decisions may be partly based on the results of a multigene quantitative reverse transcription-polymerase chain reaction (RT-PCR)-based assay: the 21-gene recurrence score (RS) test of resection specimens. When necessary, core needle biopsy (CNB) may be considered as a surrogate. Here, we evaluated the concordance in gene expression according to results from RT-PCR-based RS testing between paired CNBs and resection specimens. Methods CNBs and resection specimens from 50 breast cancer (BC) patients were tested to calculate RSs. First, we examined the concordance of the ER, PR and HER-2 status of tissue samples indicated by immunohistochemical (IHC) and RT-PCR analyses. Then, we compared the IHC findings of ER, PR, HER-2 and Ki-67 staining across paired samples. Ultimately, the RS and single-gene results for ER, PR, HER-2 and Ki-67 were explored between paired samples. Results The concordance between IHC and RT-PCR was 100%, 80.0% and 100% for ER, PR and HER-2, respectively, in both resection specimens and CNBs. The concordance for IHC ER, PR, HER-2 and Ki-67 status was 100%, 94.0%, 52.0% and 82.0%, respectively, between paired samples. RS results from paired samples showed a strong correlation. The overall concordance in RS group classification between samples was 74%, 72% and 78% based on traditional cutoffs, TAILORx cutoffs and ASCO guidelines, respectively. ER, PR, HER-2 and Ki-67 were modestly- to- strongly correlated between paired samples according to the RT-PCR results. Conclusion A modest- to- strong correlation of ER, PR, HER-2 and Ki-67 gene expression and RS between CNBs and resection specimens was observed in the present study. The 21-gene RS test could be reliably performed on CNBs. ER, PR and HER-2 status showed remarkable concordance between the IHC and RT-PCR analyses. The concordance between paired samples was high for the IHC ER, PR and Ki-67 results and low for HER-2.

Ki-67 and breast cancer prognosis: does it matter if Ki-67 level is examined using preoperative biopsy or postoperative specimen?

“…Although many IHC biomarkers such as Ki-67 have been compared in biopsy and surgical specimens, multigene assays are also compared. Although it is not yet a study with the same concept as our study, there are studies that compare the results of the Oncotype DX from biopsy with from the surgical specimen and suggest that Oncotype DX from biopsy results is also concordant and reliable with the surgical specimen [ 32 , 33 ]. As our future study, based on this study, we will begin prognostic study in luminal type and comparison of prognosis between Ki-67 and Oncotype DX or other multigene analysis.…”

High concordance of 70‐gene recurrence risk signature and 80‐gene molecular subtyping signature between core needle biopsy and surgical resection specimens in early‐stage breast cancer

“… 8 In three smaller studies using matched CNB and SR samples, researchers reported Pearson correlation coefficients ranging from 0.20 to 0.99 and overall concordance ranging from 72.0% to 95.0% using either EndoPredict, GenesWell, or Oncotype Dx multigene assays. 9 , 10 , 11 …”

“…However, multigene assays have typically been developed and tested using primary surgical specimens in an adjuvant setting. Only a few studies have determined the performance of multigene assays using CNB in recent years 8–11 . In a large unpaired study, Jakubowski et al found a similar range of Oncotype Dx Recurrence Scores between CNB and surgical resection (SR) samples (10–22 vs. 11–22, respectively) 8 .…”

“…Only a few studies have determined the performance of multigene assays using CNB in recent years. [8][9][10][11] In a large unpaired study, Jakubowski et al…”

“…8 In three smaller studies using matched CNB and SR samples, researchers reported Pearson correlation coefficients ranging from 0.20 to 0.99 and overall concordance ranging from 72.0% to 95.0% using either EndoPredict, GenesWell, or Oncotype Dx multigene assays. [9][10][11] MammaPrint is a 70-gene assay that can be used to predict the likelihood of recurrence and response to chemotherapy. 12,13 Patients identified as MammaPrint Low Risk can safely forego chemotherapy without compromising outcome, compared to those identified as High Risk for whom chemotherapy is recommended.…”