Real-Time RT-PCR Analysis for Evaluating the Her2/neu Status in Breast Cancer

Abstract

Objective: The Her2/neu 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 Her2/neu breast cancer amplification and overexpression (DNA, mRNA and protein). Methods: To accomplish this goal, we evaluated Her2/neu 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 Her2/neu results was observed, confirming that protein levels were directly related to DNA amplification. Polysomy 17 was frequently found in tumors showing Her2/neu overexpression. However, we did not find any statistically significant correlation among DNA, mRNA and protein levels, suggesting that Her2/neu could be post-transcriptionally regulated. Conclusions: There was a highagreement between Her2/neu gene amplification and protein overexpression but not mRNA expression levels. Nevertheless, IHC3+ and FISH-positive tumors indicated higher expression levels of Her2/neu 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 Her2/neu overexpression in human breast cancer in the clinical laboratory setting.

Expression Profiling of Breast Tumors Based on Human Epidermal Growth Factor Receptor 2 Status Defines Migration-Related Genes

“…This might be due to the differences in the categorization of breast tumor samples of the different studies and the variability of gains of region 17q12–21. In this study, the evaluation of HER2 mRNA expression levels showed a statistically significant correlation with DNA amplification, confirming the trend observed in our previous report [35]. However, qRT-PCR is an extremely sensitive and specific technique and there is also substantial scientific documentation supporting the variability of HER2 mRNA analysis among IHC and FISH categories [36,37,38].…”

Pathological Classification of Canine Mammary Tumor Based on Quantifying mRNA Levels of Hormonal Receptors, SATB1, and Snail in Tissue and Fine Needle Biopsy Samples

“…A recent study reported no differences in the HER2 mRNA levels between adenomas and carcinomas or between presence and absence of lymph node involvement of cMTs [23]. In human breast cancer, reports on the interaction between mRNA expression and HER2 protein or DNA amplification levels did not reach agreement [5,13]. Since there was no significant difference in HER2 expression among cMT tissue samples in the present study, HER2 was not assessed in FNB samples.…”

Assessment of HER2 gene status in breast carcinomas with polysomy of chromosome 17

“…In addition, increased CEP17 copy number is frequently found in tumors showing HER2 overexpression, including those with a borderline (2þ) score, as confirmed in our study. [18][19][20] Our series included unselected (no prior IHC determination of HER-2/neu protein) and selected (equivocal IHC staining results) cases, reflecting our referral laboratory's mixture of cases received from different institutions.…”