Microwave enhancement of CISH for HER2 oncogene.

Area of Science:

• Oncology
• Molecular Pathology
• Biotechnology

Background:

• HER2 amplification is a key biomarker in breast cancer diagnostics.
• Chromogenic in situ hybridization (CISH) is used for HER2 testing.
• Standard CISH protocols may have limitations in signal consistency.

Purpose of the Study:

• To modify the Zymed Spot-Light HER2 CISH kit procedure.
• To evaluate the efficacy of microwave (MW) irradiation for heat pretreatment.
• To improve HER2 signal detection and assessment in invasive breast carcinoma.

Main Methods:

• Modified Zymed Spot-Light HER2 CISH kit procedure using MW irradiation for heat pretreatment.
• Citrate buffer (10 mmol/L, pH 6.0) at 98°C for 10 minutes with controlled time/temperature oven.
• Examined 48 invasive breast carcinoma cases (18x 3+, 18x 2+, 12x 1+ by IHC) using both modified and standard CISH methods.

Main Results:

• MW irradiation resulted in a greater number of hybridization signals in amplified tumor cells.
• Benign cells and lymphocytes showed 2 clear dots with MW retrieval.
• MW exposed sections displayed larger clusters, enabling easier identification of amplified tumors.
• Crisp staining and absence of background precipitation were observed with MW method.

Conclusions:

• The modified MW irradiation procedure enhances HER2 CISH signal detection.
• This method offers improved accuracy and ease of interpretation for HER2 amplification in breast cancer.
• MW retrieval is a promising alternative to standard heat pretreatment for HER2 CISH.