Fluorescent in Situ Hybridization and Real-Time Quantitative Polymerase Chain Reaction to Evaluate HER-2/neu Status in Breast Cancer

Abstract

<strong><em>Background</em></strong><strong><em>:</em></strong>Breast cancer remains the most common and second lethal cancer in females. <em>HER-2/neu</em> is one of the most important amplified oncogene in breast cancer. The amplification of <em>HER-2</em> is correlated with decreased survival, metastasis, and early recurrence. The amplification of <em>HER-2/neu</em> 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.<br /> <strong><em>Methods</em></strong><strong>: </strong>Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) methods are options to evaluate <em>HER-2</em> expression. The current study aimed at identifying the correlation between FISH and real-time polymerase chain reaction (PCR) in measuring <em>HER-2</em> expression.<br /> <strong><em>Results</em></strong><strong>: </strong>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 <em>HER-2</em> gene, confirmed by FISH as a gold standard method. The real-time PCR ratio was HER-2 gene by FISH as a gold standard assay.<br /> <strong><em>Conclusion</em></strong><strong>: </strong>Despite the fact that real-time PCR is a promising method to evaluate <em>HER-2</em> 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 <em>HER-2</em> over expression.