Nucleic acid sequence-based amplification in formalin-fixed and paraffin-embedded breast-cancer tissues.

AIM: To evaluate the nucleic acid sequence-based amplification (NASBA) technique to amplify mRNA isolated from formalin-fixed and paraffin-embedded (FFPE) breast-cancer tissues. METHODS: RNA was extracted from archived, 10-year-old FFPE tissues, and selected genes, namely ribosomal protein S18 (RPS18), epidermal growth factor receptor 2 (HER2), estrogen receptor alpha (ERα), Y box binding protein (YBX-1), matrix metallopeptidase 11 (MMP11), caspase 8 (CASP8) and superoxide dismutase 2 (SOD2), were amplified by NASBA. RESULTS: Despite strong degradation of the template, RNA amplification of all tested genes resulted in strong hybridisation signals. Sensitivity tests showed that the RPS18 NASBA assay was more sensitive than real-time RT-PCR used as a reference method. The sensitivity of the HER2, ERα, MMP11, YBX1, CASP8 and SOD2 NASBA assay was comparable with RT-PCR targeted to the respective genes. CONCLUSIONS: The results obtained indicate that NASBA is suitable to amplify with high specificity and sensitivity, even strongly degraded RNA isolated from FFPE tissues, and therefore can complement already-existing amplification techniques such as RT-PCR for analysis of such tissues.