Trastuzumab altered the expression of genes that are essential for cardiac functions.

<p>(a) Heatmap representation of differentially expressed genes in the trastuzumab-treated animals compared to the control vehicle injected animals (blue = downregulation and red = upregulation); n=4 for each group. (b) Bar graph showing microarray results as Log₂ of fold change. (c) Bar graph showing the qPCR validation of randomly selected genes from the microarray data. Results are shown as log₂ of fold change. Analysis of variance was used to determine those probe sets significantly different between the two groups. The gene list was filtered with a fold-change cutoff of 2.