RESUMO
BACKGROUND AND OBJECTIVE: The assessment of human epidermal growth factor receptor 2 (HER2) status has become of great importance in the diagnosis of breast cancer. The aim of this study was to investigate the diagnostic value of quantitative Polymerase Chain Reaction (qPCR) and Chromogenic In Situ Hybridization (CISH) to assess HER2 status of biopsy specimens. METHODS: To elucidate the status of HER2 gene amplification, biopsies of breast carcinoma from 120 patients with 2+ IHC status were analyzed by qPCR and CISH. RESULTS: The results of the two experiments were compared, and it was depicted that the concordance rate between CISH and qPCR assays was 88.1%.The quantification of HER2 gene with CISH and qPCR showed that there was a significant correlation (p value= 0.0001 and r= 0.808). CONCLUSION: The results of this research support the idea that qPCR is a precise and reproducible technique, which can be employed as a supplementary method to evaluate HER2 status.
RESUMO
BACKGROUND: Breast cancer remains the most common and second lethal cancer in females. HER-2/neu is one of the most important amplified oncogene in breast cancer. The amplification of HER-2 is correlated with decreased survival, metastasis, and early recurrence. The amplification of HER-2/neu gene and synthesis of the protein are reported in 10%-34% of breast cancer cases associated with tumor size, advanced tumor stage, high-grade tumor, young age at diagnosis, absence of steroid hormone receptor, and lymph node involvement. METHODS: Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) methods are options to evaluate HER-2 expression. The current study aimed at identifying the correlation between FISH and real-time polymerase chain reaction (PCR) in measuring HER-2 expression. RESULTS: The study investigated the performance of the real-time PCR as measured against FISH method in IHC +2 borderline cases. In a total of 120 IHC 2+ samples, 58.3% were negative and 41.6% positive for HER-2 gene, confirmed by FISH as a gold standard method. The real-time PCR ratio was <1.8 for a majority (82.8%) of the tumor samples with unamplified HER-2 gene by FISH as a gold standard assay. CONCLUSION: Despite the fact that real-time PCR is a promising method to evaluate HER-2 over expression and a supplementary array to FISH, according to the results of the present study it cannot be utilized instead of gold standard techniques; therefore, additional studies should be carried out to appraise the value of this method to evaluate HER-2 over expression.