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Reliability of Ki67-Labeling Index in Core Needle Biopsy Specimens of ER+/HER2- Breast Cancers

  • 0Department of Surgery, Division of General Thoracic Surgery and Breast and Endocrine Surgery, Yonago, Japan.
Pathology International +

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March 10, 2025

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March 10, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

Ki67-labeling index (LI) in core needle biopsy (CNB) reliably classifies ER+/HER2- invasive breast carcinoma (IBC) into Luminal A-like and Luminal B-like subtypes. However, factors like negative progesterone receptor and tumor size influence Ki67-LI discordance between CNB and surgical resection.

Area Of Science

  • Oncology
  • Pathology
  • Molecular Diagnostics

Background

  • Reliable Ki67-labeling index (LI) assessment is crucial for classifying ER+/HER2- invasive breast carcinoma (IBC) into Luminal A-like (LumA) and Luminal B-like (LumB) subtypes.
  • Discordance in Ki67-LI between core needle biopsy (CNB) and surgical resection (SR) can impact clinical decisions.
  • Understanding factors influencing this discordance is essential for accurate subtyping and prognosis.

Purpose Of The Study

  • To evaluate the reliability of Ki67-LI in CNB for ER+/HER2- IBC classification.
  • To identify factors contributing to Ki67-LI discordance between CNB and SR specimens.
  • To assess the prognostic value of Ki67-LI in CNB and SR for disease-free survival.

Main Methods

  • Retrospective analysis of 326 ER+/HER2- IBC cases with available Ki67-LI data from both CNB and SR.
  • Spearman's rank correlation to assess Ki67-LI concordance between CNB and SR.
  • Survival analysis (log-rank test) on 122 patients to evaluate disease-free survival based on Ki67-LI cutoffs.
  • Multivariate analysis to identify factors affecting Ki67-LI discordance.

Main Results

  • Ki67-LI in CNB showed a moderate correlation (Spearman's rho = 0.683) with SR.
  • Higher Ki67-LI (≥20%) in both CNB and SR was significantly associated with shorter disease-free survival (p<0.001).
  • Negative progesterone receptor (p=0.002) and pathological tumor size >2 cm (p<0.001) were significant factors for Ki67-LI discordance at 20% and 30% cutoffs, respectively.
  • Histological grade III impacted concordance at the 20% cutoff (p=0.01).

Conclusions

  • Ki67-LI assessment in CNB is valuable for classifying ER+/HER2- IBC into LumA and LumB subtypes.
  • Clinical decisions based on CNB Ki67-LI should consider potential discordance due to prognostic factors.
  • Prognostic factors such as PgR status and tumor size necessitate careful interpretation of Ki67-LI in CNB for treatment stratification.

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