Ancillary Prognostic and Predictive Testing in Breast Cancer: Focus on Discordant, Unusual, and Borderline Results

Surg Pathol Clin. 2018 Mar;11(1):147-176. doi: 10.1016/j.path.2017.09.006.

Abstract

Ancillary testing in breast cancer has become standard of care to determine what therapies may be most effective for individual patients with breast cancer. Single-marker tests are required on all newly diagnosed and newly metastatic breast cancers. Markers of proliferation are also used, and include both single-marker tests like Ki67 as well as panel-based gene expression tests, which have made more recent contributions to prognostic and predictive testing in breast cancers. This review focuses on pathologist interpretation of these ancillary test results, with a focus on expected versus unexpected results and troubleshooting borderline, unusual, or discordant results.

Keywords: Breast cancer; ER testing; Fluorescence in situ hybridization (FISH); HER2 testing; Molecular testing; OncotypeDX; Predictive testing.

Publication types

  • Review

MeSH terms

  • Antineoplastic Agents / therapeutic use
  • Biomarkers, Tumor / analysis*
  • Biomarkers, Tumor / genetics
  • Breast Neoplasms / diagnosis*
  • Breast Neoplasms / drug therapy
  • Diagnostic Tests, Routine
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunohistochemistry / standards
  • In Situ Hybridization, Fluorescence / standards
  • Molecular Targeted Therapy
  • Neoplasm Staging / methods
  • Practice Guidelines as Topic
  • Predictive Value of Tests*
  • Prognosis
  • Receptor, ErbB-2 / analysis

Substances

  • Antineoplastic Agents
  • Biomarkers, Tumor
  • Receptor, ErbB-2