Real-time RT-PCR: a complementary method to detect HER-2 status in breast carcinoma

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Accurate HER-2 status determination is crucial for treating HER-2 overexpressed invasive breast carcinoma with Herceptin.
• Immunohistochemistry (IHC) is a common method, but quantitative mRNA expression analysis offers complementary insights.

Purpose of the Study:

• To retrospectively evaluate HER-2 mRNA expression levels using quantitative real-time RT-PCR (Q-RT-PCR).
• To compare Q-RT-PCR results with IHC for HER-2 status determination in primary breast carcinomas.
• To establish cut-off values for altered mRNA expression using normal breast tissue samples.

Main Methods:

• Quantitative real-time RT-PCR (Q-RT-PCR) was performed on 44 primary breast carcinoma tissue samples.
• HER-2 mRNA expression levels were normalized using 20 normal breast tissue RNA samples to define expression categories.
• Results were compared with conventional immunohistochemistry (IHC) staining.

Main Results:

• HER-2 gene expression was categorized into normal, moderate, and strong overexpression groups.
• Overexpression was observed in a significant portion of samples: 38% strong, 25% moderate, and 36.3% normal expression.
• A high concordance rate of 84% was found between Q-RT-PCR and IHC, with only minor discordances in 7 cases.

Conclusions:

• Q-RT-PCR is a reliable and complementary method for quantifying HER-2 mRNA expression.
• The high concordance with IHC supports its utility in determining HER-2 status for treatment selection.
• This quantitative approach provides valuable data for personalized breast cancer therapy.