QUANTITATIVE-ANALYSIS OF HER-2 NEU (ERBB2) GENE-EXPRESSION USING REVERSE-TRANSCRIPTASE POLYMERASE CHAIN-REACTION/

Inappropriate expression of Her-2/neu (ERBB2) gene has been associated with impaired breast cancer prognosis, suggesting a functional role i n tumor progression. Herein we describe a quantitative method for anal ysis of Her-2/neu gene messenger RNA (mRNA), which employs reverse tra nscriptase polymerase chain reaction (RT-PCR) on a 10-mum cryostat sec tion. The technique combines modified RNA extraction with complementar y DNA (cDNA) synthesis to achieve a high level of sensitivity. Utilizi ng this PCR-based gene expression assay, we were able to quantitate va riable amounts of Her-2/neu mRNA in cell lines with established levels of gene expression and in clinical human breast cancer specimens. In clinical samples, mRNA levels correlated with intensity of immunoperox idase staining for corresponding oncoprotein. We conclude that PCR-bas ed mRNA quantitation can be applied to quantitative analysis of Her-2/ neu gene expression, and potentially many other genes, in samples of l imited size.