Comparison of the results of PCR analysis of gene expression in breast cancer tissue specimens stabilized in formalin and RNAlater.

We compared the results of real-time PCR analysis of gene expression in paired specimens breast cancer tissue fixed in RNAlater (Qiagen) stabilization reagent (FF samples) and in formalin (FFPE samples). A clear-cut linear relationship (correlation coefficient 0.76 ± 0.07) was detected between the gene expression logarithm values in FF and FFPE samples. This fact suggests that collections of paraffin blocks with formalin-fixed tissue specimens from patients with a many-year disease history can be effectively used in modern studies.