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Åke Borg

Åke Borg

Principal investigator

Åke Borg

Sample preparation approach influences pam50 risk of recurrence score in early breast cancer

Author

  • Tonje G. Lien
  • Hege Oma Ohnstad
  • Ole Christian Lingjærde
  • Johan Vallon-Christersson
  • Marit Aaserud
  • My Anh Tu Sveli
  • Åke Borg
  • Øystein Garred
  • Elin Borgen
  • Bjørn Naume
  • Hege Russnes
  • Therese Sørlie
Show all

Summary, in English

The PAM50 gene expression subtypes and the associated risk of recurrence (ROR) score are used to predict the risk of recurrence and the benefits of adjuvant therapy in early-stage breast cancer. The Prosigna assay includes the PAM50 subtypes along with their clinicopathological fea-tures, and is approved for treatment recommendations for adjuvant hormonal therapy and chemotherapy in hormone-receptor-positive early breast cancer. The Prosigna test utilizes RNA extracted from macrodissected tumor cells obtained from formalin-fixed, paraffin-embedded (FFPE) tissue sections. However, RNA extracted from fresh-frozen (FF) bulk tissue without macrodissection is widely used for research purposes, and yields high-quality RNA for downstream analyses. To in-vestigate the impact of the sample preparation approach on ROR scores, we analyzed 94 breast carcinomas included in an observational study that had available gene expression data from macro-dissected FFPE tissue and FF bulk tumor tissue, along with the clinically approved Prosigna scores for the node-negative, hormone-receptor-positive, HER2-negative cases (n = 54). ROR scores were calculated in R; the resulting two sets of scores from FFPE and FF samples were compared, and treatment recommendations were evaluated. Overall, ROR scores calculated based on the macro-dissected FFPE tissue were consistent with the Prosigna scores. However, analyses from bulk tissue yielded a higher proportion of cases classified as normal-like; these were samples with relatively low tumor cellularity, leading to lower ROR scores. When comparing ROR scores (low, intermedi-ate, and high), discordant cases between the two preparation approaches were revealed among the luminal tumors; the recommended treatment would have changed in a minority of cases.

Department/s

  • Breastcancer-genetics
  • LUCC: Lund University Cancer Centre
  • Familial Breast Cancer

Publishing year

2021-12

Language

English

Publication/Series

Cancers

Volume

13

Issue

23

Document type

Journal article

Publisher

MDPI AG

Topic

  • Cancer and Oncology

Keywords

  • Breast cancer
  • Bulk
  • FFPE
  • Fresh-frozen
  • Macrodissection
  • PAM50
  • Prosigna
  • Risk of recurrence score

Status

Published

Research group

  • Familial Breast Cancer

ISBN/ISSN/Other

  • ISSN: 2072-6694