Multiple drug resistance-related messenger RNA expression in archival formalin-fixed paraffin-embedded human breast tumour tissue.

A method is described by which RNA, suitable for reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, can be extracted from formalin-fixed paraffin-embedded (FFPE) tissues and subsequently used for detecting the expression of several genes. Using this technique, RNA can be extracted from specimens, quantified, reverse transcribed and regions of interest amplified and analysed within 36 h. The tissue specimens included in this study were from human breast carcinoma, investigating a range of genes associated with the development and/or maintenance of multiple drug resistance (MDR). This technique, applied to archival tissues, offers great potential for increasing our understanding of alterations in expression levels of genes associated with MDR. The method developed is also applicable to studies on expression of other genes in paraffin-embedded tissues.