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Protocol for HER2 FISH Using a Non-cross-linking, Formalin-free Tissue Fixative to Combine Advantages of Cryo-preservation and Formalin Fixation
Published on: December 25, 2017
Delay to formalin fixation effect on breast biomarkers.
Thaer Khoury1, Sheila Sait, Helena Hwang
1Department of Pathology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. thaer.khoury@roswellpark.org
Summary
Delays in formalin fixation beyond 1 hour can compromise breast cancer biomarker accuracy, potentially affecting treatment decisions and patient outcomes. Prompt fixation is crucial for reliable hormone receptor and HER2 analysis.
Area of Science:
- Oncology
- Pathology
- Biomarker Analysis
Background:
- Formalin fixation is critical for preserving tissue integrity.
- Delayed fixation can impact the accuracy of diagnostic biomarkers.
- Accurate breast cancer biomarkers are essential for guiding adjuvant therapy and prognosis.
Purpose of the Study:
- To investigate the impact of progressive delays in formalin fixation on key breast cancer biomarkers.
- To establish optimal fixation timeframes for reliable biomarker analysis.
Main Methods:
- Ten invasive breast cancer specimens were analyzed.
- Tumor sections were fixed at intervals from 0 to 8 hours, with one stored overnight.
- Estrogen receptor, progesterone receptor, and HER2 analyses were performed using immunohistochemistry and FISH.
- Statistical tests were employed to assess significance.
Main Results:
- Estrogen and progesterone receptor scores declined significantly after 1-2 hours of fixation delay.
- HER2 fluorescence in situ hybridization (FISH) interpretation was compromised starting at 1 hour and became statistically significant at 2 hours.
- Overnight storage further reduced biomarker integrity.
Conclusions:
- Formalin fixation delays exceeding 1 hour negatively affect breast cancer biomarker reliability.
- Specimen storage overnight should be avoided to maintain biomarker quality.
- Recommendations emphasize prompt formalin fixation (within 1 hour) for accurate breast cancer biomarker assessment.
