Microarray data analysis. (A) The heat map was generated using hierarchical cluster analysis to show distinct miRNA expression patterns in splenic lymphocytes between placebo- and estrogen-treated mice. The intensity values were Log2 transformed, centered by the mean of individual genes across all 4 samples, and then subjected to cluster analysis for generating the heat map. The color bar was extracted to show the color contrast level of the heat map. Red and green indicate high expression level and low expression level, respectively. (B) miRNAs that demonstrated statistically different expression levels between freshly isolated splenic lymphocytes from placebo- and estrogen-treated mice (P < .05) are listed. Fold-changes in miRNA expression were calculated as the ratio of mean intensity values between estrogen- and placebo-treated mice.