Analysis of HER۲ gene amplification using Differential PCR in breast cancer patients of Isfahan Province

Background: Amplification of HER۲ is seen in ۲۰-۳۰% of breast cancer cases. Measurement of HER۲ gene amplification appears to be of vital importance in planning the treatment schedule for patients with breast carcinoma. The aim of our study was to evaluate HER۲ amplification status in malignant and benign breast tumors by differential PCR (dPCR). Materials and Methods: The genomic DNA was extracted using the phenol/chloroform extraction procedure from ۷۶ different breast tissues. Differential PCR was performed using the DNA samples isolated from fresh and paraffin- embedded breast cancer tissues. The relative copy number ratio of target gene (HER۲) to control gene ( INF-γ ) was measured. dPCR products were then separated by electrophoresis using ۲% agarose gel. The intensity of HER۲ and INFγ bands were determined for each sample by ImageJ software. Results: According to the ratio between the band intensity of HER۲ to INFγ in tumour and also normal samples, ۷% and ۲۶% rates of HER۲ amplification were observed in benign and malignant samples respectively. The ratio showed a ۲-۵ fold increase in HER۲ gene copy number for tissues with HER۲ amplification whereas, a one-fold increase was found in other samples. Conclusion: Differential PCR provides a relatively rapid and inexpensive technique to assess the HER۲ gene amplification, especially alongside immunohistochemistry as a routine assessing method .

Keywords:

HER۲ amplification , breast cancer , differential PCR