Heat map of the Pearson’s correlation matrix for the mRNA expression of AP-1 members. Pairwise correlation analyses were performed for all assayed mRNAs. Blue represents positive correlation for a given gene pair, and red represents negative correlation. C-Jun and c-Fos showed strong positive correlation (r = 0.78). In addition, there were moderate positive correlations between Jun-B and Jun-D (r = 0.63), and between Fra-2 and Jun-D (r = 0.65).