Summary of Pearson correlation coefficients between microarray data and real-time PCR data. The 32 possible combinations containing one or more of 5 endogenous controls are shown as columns. All genes of interest are shown as rows. The color scale for the correlation coefficient is shown below. Rows are sorted top to bottom by mean correlation coefficient across all endogenous control combinations. Columns are sorted left to right by mean correlation coefficient across all genes. As a simplification, microarray data for genes with more than one probe set are taken as the per-sample mean value of all probe sets. Creating the same figure with values per probe set would give a figure with 34 rows (one for each probe set in the genes of interest), with slightly different correlation coefficients but would not change the sorting of the columns overall. Exact distribution using per-probe-set analysis can be extracted from Additional file 1. Real-time PCR data on LOX and ALOX12 has large deviations on replicate values as described in the text and can be omitted without changing the results.