Single-day HER2neu amplification assessment using chip-based digital PCR in formalin-fixed paraffin-embedded breast carcinoma tissue
Received 1 January 2018
Accepted for publication 3 May 2018
Published 23 July 2018 Volume 2018:10 Pages 121—129
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Professor Pranela Rameshwar
Parth S Shah,1,2 Shiva Murarka,1 Anupam Joshi,3 Bhavna Mehta,3 Vipal Parmar,3 Nidhi Shah,1,4 Khushbu Patel,1 Jacob Sands5
1Department of Molecular Genetics, Supratech Micropath Laboratory and Research Institute, Ahmedabad, India; 2Department of Medicine, Lahey Hospital and Medical Center, Burlington, MA, USA; 3Department of Histopathology, Supratech Micropath Laboratory and Research Institute, Ahmedabad, India; 4Department of Pediatrics, Nassau University Medical Center, East Meadow, NY, USA; 5Department of Hematology and Oncology, Lahey Hospital and Medical Center, Burlington, MA, USA
Introduction: Human epidermal growth factor receptor 2 (HER2) amplification is present in almost 15%–20% of breast cancer tumors, making it an important parameter for testing. The present study was designed to evaluate a chip-based digital PCR (dPCR) system for assessing HER2 amplification from formalin-fixed paraffin-embedded breast carcinoma tissue and to compare this system with immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).
Materials and methods: A total of 84 breast carcinoma tissue samples were analyzed by IHC, FISH, and chip-based dPCR in a blinded manner.
Results: All nine IHC-positive and 35 IHC-negative samples had equivalent results with dPCR, taking an amplification ratio threshold of 1.8 as a positive result. Of the 40 IHC equivocal samples, 10 were assessed as positive, 27 as negative, and three as equivocal by dPCR.
Conclusion: These results demonstrate that chip-based dPCR is suitable for HER2 amplification detection in formalin-fixed paraffin-embedded samples in a clinical setting, providing the advantages of superior turnaround time, cost-effectiveness, and increased precision with absolute quantification compared with conventional tests such as FISH and IHC. This methodology was especially beneficial in tissue samples with low DNA concentration.
Keywords: HER2, digital PCR, IHC, FISH, breast cancer
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