RNA-seq from archival FFPE breast cancer samples: Molecular pathway fidelity and novel discovery

Nathan D. Pennock, Sonali Jindal, Wesley Horton, Duanchen Sun, Jayasri Narasimhan, Lucia Carbone, Suzanne S. Fei, Robert Searles, Christina A. Harrington, Julja Burchard, Sheila Weinmann, Pepper Schedin, Zheng Xia

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Background: Formalin-fixed, paraffin-embedded (FFPE) tissues for RNA-seq have advantages over fresh frozen tissue including abundance and availability, connection to rich clinical data, and association with patient outcomes. However, FFPE-derived RNA is highly degraded and chemically modified, which impacts its utility as a faithful source for biological inquiry. Methods: True archival FFPE breast cancer cases (n = 58), stored at room temperature for 2-23 years, were utilized to identify key steps in tissue selection, RNA isolation, and library choice. Gene expression fidelity was evaluated by comparing FFPE data to public data obtained from fresh tissues, and by employing single-gene, gene set and transcription network-based regulon analyses. Results: We report a single 10 μm section of breast tissue yields sufficient RNA for RNA-seq, and a relationship between RNA quality and block age that was not linear. We find single-gene analysis is limiting with FFPE tissues, while targeted gene set approaches effectively distinguish ER+ from ER- breast cancers. Novel utilization of regulon analysis identified the transcription factor KDM4B to associate with ER+ disease, with KDM4B regulon activity and gene expression having prognostic significance in an independent cohort of ER+ cases. Conclusion: Our results, which outline a robust FFPE-RNA-seq pipeline for broad use, support utilizing FFPE tissues to address key questions in the breast cancer field, including the delineation between indolent and life-threatening disease, biological stratification and molecular mechanisms of treatment resistance.

Original languageEnglish (US)
Article number195
JournalBMC Medical Genomics
Volume12
Issue number1
DOIs
StatePublished - Dec 19 2019

Keywords

  • Archival tissue
  • Breast Cancer
  • Estrogen receptor
  • FFPE
  • Formalin fixed paraffin embedded
  • KDM4B
  • RNA sequencing
  • RNA-Seq, genomics
  • RNA-seq
  • Regulon

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

Fingerprint Dive into the research topics of 'RNA-seq from archival FFPE breast cancer samples: Molecular pathway fidelity and novel discovery'. Together they form a unique fingerprint.

  • Cite this