Real-time RT-PCR analysis for evaluating the Her2eu status in breast cancer.

摘要

OBJECTIVE: The Her2eu status is of great clinical value in breast tumor patients. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) techniques are the test of choice for many practicing pathologies. The main objective of this retrospective study was to investigate the relationship between Her2eu breast cancer amplification and overexpression (DNA, mRNA and protein). METHODS: To accomplish this goal, we evaluated Her2eu mRNA expression by real-time quantitative RT-PCR, gene amplification by FISH and protein expression by IHC. RESULTS: An excellent correlation between FISH and IHC Her2eu results was observed, confirming that protein levels were directly related to DNA amplification. Polysomy 17 was frequently found in tumors showing Her2eu overexpression. However, we did not find any statistically significant correlation among DNA, mRNA and protein levels, suggesting that Her2eu could be post-transcriptionally regulated. CONCLUSIONS: There was a highagreement between Her2eu gene amplification and protein overexpression but not mRNA expression levels. Nevertheless, IHC3+ and FISH-positive tumors indicated higher expression levels of Her2eu mRNA by RT-PCR than those observed in IHC and FISH-negative tumors. These findings question the relevance of quantitative RT-PCR in routine assessment of Her2eu overexpression in human breast cancer in the clinical laboratory setting.