With the advances in the field of molecular biology and its applications in the clinical practice during the recent years, it has become crucial to perform molecular analyses on limited amount of tissue obtained through biopsies. Additionally, tissue is fixed in formalin and further embedded in paraffin (FFPE), a procedure which causes extensive degradation of nucleic acids, mainly RNAs. Furthermore, when studying gene expression profiles of a set of genes, which present physiologically low expression, the number of transcripts is low and cannot be detected. In this study we focus on amplifying effectively cDNA molecules synthesized from small amounts of initial RNA before analyzing the expression levels through quantitative polymerase chain reaction (qPCR). By introducing the preamplification step in the procedure, we achieved highly efficacious detection and quantification of expression levels of low-expression genes.
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