Correlation between HER2 gene copy number and immunohistochemistry categories in HER2-negative breast cancer: diagnostic utility for differentiating HER2-null, ultralow, and low tumors

Key Points

• The research aims to explore the relationship between HER2 gene copy number and immunohistochemistry (IHC) categories in HER2-negative breast cancer.
• Analyzed HER2 gene copy number and immunohistochemistry categories in breast cancer samples.
• Compared results between HER2-low, HER2-null, and low tumors.
• Statistical analysis conducted to evaluate correlations.
• HER2 gene copy number showed a positive correlation with protein expression as per IHC categories.
• HER2-low tumors had statistically higher gene copy numbers than HER2-null tumors.
• Significant overlap in copy number ranges limits effective distinction between HER2-low and HER2-null tumors.