Automated immunohistochemical estrogen receptor in fixed embedded breast carcinomas

Area of Science:

• Oncology
• Pathology
• Biochemistry

Background:

• Accurate estrogen receptor (ER) status is crucial for breast cancer treatment decisions.
• Evaluating ER in formalin-fixed, paraffin-embedded (FFPE) tissues presents challenges compared to fresh or frozen samples.

Purpose of the Study:

• To compare the accuracy of an automated immunohistochemical method (Method 1) for ER detection in FFPE breast cancer tissues against other methods and biochemical assays.
• To assess the clinical utility of ER immunohistochemistry on FFPE tissues.

Main Methods:

• Immunohistochemical assessment of ER in 68 breast carcinomas using formalin-fixed, paraffin-embedded (FFPE) sections with automated Pronase predigestion and alkaline phosphatase detection (Method 1).
• Comparison with automated peroxidase-antiperoxidase method (Method 2), ER immunostain on frozen sections (Method 3), and dextran-coated charcoal (DCC) biochemical assay.

Main Results:

• Method 1 (FFPE) showed 54% sensitivity compared to DCC assay, Method 2 showed 25%, and Method 3 (frozen) showed 89%.
• Method 1 sensitivity improved to 74% for cases with DCC results > 50 fmol/mg protein.
• Positive ER results from Method 1 on FFPE tissues provide valuable clinical information.

Conclusions:

• Automated ER immunohistochemistry on FFPE tissues (Method 1) is clinically useful for positive results.
• Negative results require cautious interpretation due to potential low receptor levels or improper tissue preservation.
• Method 1 offers a viable alternative when fresh tissue or frozen sections are unavailable, acknowledging its limitations.