Immunohistochemical progesterone receptor assay. Measurement by image analysis

Area of Science:

• Oncology
• Biochemistry
• Pathology

Background:

• Accurate measurement of progesterone receptor (PgR) is crucial for breast cancer treatment decisions.
• Traditional biochemical dextran-coated charcoal assay (DCC) requires fresh tissue, which is not always available.

Purpose of the Study:

• To evaluate the efficiency of image analysis for quantifying PgR in immunohistochemically stained breast carcinoma tissue.
• To compare image analysis results with the standard DCC assay.

Main Methods:

• 94 primary breast carcinoma samples were analyzed using DCC assay and immunohistochemistry.
• Immunohistochemical staining for PgR was performed on frozen sections.
• Quantitative analysis of percentage nuclear area immunopositivity (PNA) was conducted using an image analyzer (CAS 200).
• Histologic scoring was also performed via microscopy.

Main Results:

• A positive correlation was observed between the DCC assay and both histologic score (r=0.82) and PNA (r=0.69).
• Established cutoff points for histologic score (60) and PNA (6.5%) demonstrated high positive predictive values (100%).
• Image analysis (PNA) showed good sensitivity and specificity, correlating well with biochemical PgR levels.

Conclusions:

• Image analysis of PgR-immunostained sections is a viable and efficient alternative to the DCC assay.
• This method is particularly useful when fresh tissue for biochemical assays is unavailable.
• Quantitative image analysis provides reliable PgR measurement in breast cancer diagnostics.