Reinventing Nuclear Histo-score Utilizing Inherent Morphologic Cutoffs: Blue-brown Color H-score (BBC-HS).

Area of Science:

• Pathology
• Biomarker Analysis
• Histology

Background:

• Immunohistochemistry (IHC) is crucial for diagnosing and predicting disease outcomes using biomarkers.
• Standardizing IHC scoring, especially for graded intensity (1+, 2+, 3+), is essential for reproducible results.
• Current methods like H-score require consistent interpretation of staining intensity.

Purpose of the Study:

• To introduce and validate a novel scoring system, the Blue-brown Color H-score (BBC-HS), for nuclear IHC biomarker assays.
• To improve the standardization and reproducibility of IHC staining intensity assessment.
• To establish reliable cutoffs for positive/negative results and graded intensity categories.

Main Methods:

• Developed BBC-HS based on the color interaction between hematoxylin (blue) and diaminobenzidine (brown) for nuclear IHC.
• Assessed MUM1 nuclear staining in diffuse large B-cell lymphoma cases using BBC-HS with 12 readers.
• Calculated Krippendorff alpha (K-alpha) and intraclass correlation coefficient (ICC) to evaluate inter-reader reliability.

Main Results:

• BBC-HS demonstrated high reliability, with K-alpha of 0.76 for percent positive score (PPS) and 0.86 for H-score.
• ICC values were also high, reaching 0.92 for PPS and 0.96 for H-score, indicating strong agreement between readers.
• Minimal bias was observed among readers, suggesting the method's robustness and ease of training.

Conclusions:

• The proposed BBC-HS cutoffs provide highly reliable and reproducible scoring for nuclear IHC biomarker assays.
• BBC-HS is easily teachable and applicable to both manual assessment and image analysis.
• This scoring system facilitates the development of new, dependable scoring schemes for IHC biomarkers.