Plasma HER2 amplification in cell-free DNA during neoadjuvant chemotherapy in breast cancer

Troels Bechmann*, Rikke Fredslund Andersen, Niels Pallisgaard, Jonna Skov Madsen, Else Maae, Erik Hugger Jakobsen, Anne Marie Bak Jylling, Karina Dahl Steffensen, Anders Jakobsen

*Corresponding author

Publikation: Bidrag til tidsskriftTidsskriftartikelpeer review

Abstract

Purpose: Measurement of human epidermal growth factor receptor 2 (HER2) gene amplification in cell-free DNA (cfDNA) is an evolving technique in breast cancer, enabling liquid biopsies and treatment monitoring. The present study investigated the dynamics of plasma HER2 gene copy number and amplification in cfDNA during neoadjuvant chemotherapy. Patients and methods: The study included 50 patients from a prospective cohort analyzed during neoadjuvant chemotherapy. Fifty healthy women with no history of cancer served as control group and 15 patients with metastatic breast cancer were used to validate the assay. Total cfDNA and HER2 gene amplification were measured by quantitative real-time polymerase chain reaction. Results: Plasma HER2 gene copy number (p = 0.794), HER2 gene amplification (p = 0.127) and total cfDNA (p = 0.440) did not differ significantly from the levels in the control group. Eighteen patients (36 %) obtained pathological complete response (pCR). HER2 gene copy number before the operation was significantly higher than the baseline level (p < 0.0001), but there was no difference between patients with and without pCR (p = 0.569). Likewise, there was no difference in plasma HER2 gene amplification between tissue HER2-positive and -negative patients (p = 0.754). Conclusions: The results indicate that neither total cfDNA nor HER2 gene copy number is elevated in primary breast cancer patients compared to healthy controls. The level of both parameters increased during neoadjuvant chemotherapy, but without any relation to treatment effect. There was no indication of plasma HER2 gene amplification in the HER2-positive patients in the neoadjuvant setting.

OriginalsprogEngelsk
TidsskriftJournal of Cancer Research and Clinical Oncology
Vol/bind139
Udgave nummer6
Sider (fra-til)995-1003
Antal sider9
ISSN0171-5216
DOI
StatusUdgivet - jun. 2013
Udgivet eksterntJa

Emneord

  • Breast cancer
  • Cell-free DNA
  • HER2 amplification
  • Neoadjuvant chemotherapy

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