Scatter-plots of RNA concentration and RNU6-2 measurements of RNA from dissectates of formalin-fixed tissue sections. Total RNA in 23 samples was quantified by RiboGreen assay (black) or absorbance spectrophotometry at 260 nm (grey). Level of RNU6-2 in the RNA preparations was determined as quantification cycle (C
) values obtained in reverse transcription-PCR assays. The best lines of fit with the least squares method are also shown.