MULTIPLE-DRUG RESISTANCE-RELATED MESSENGER-RNA EXPRESSION IN ARCHIVALFORMALIN-FIXED PARAFFIN-EMBEDDED HUMAN BREAST-TUMOR TISSUE

A method is described by which RNA, suitable for reverse transcriptase -polymerase chain reaction (RT-PCR) analysis, can be extracted from fo rmalin-fixed paraffin-embedded (FFPE) tissues and subsequently used fo r 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 spe cimens included in this study were from human breast carcinoma, invest igating a range of genes associated with the development and/or mainte nance of multiple drug resistance (MDR). This technique, applied to ar chival tissues, offers great potential for increasing our understandin g of alterations in expression levels of genes associated with MDR. Th e method developed is also applicable to studies on expression of othe r genes in paraffin-embedded tissues.