Transfected cell microarray is a versatile, efficient, and cost-reducing technology [1,3,4] that can contribute to further understanding of gene functions and regulatory mechanisms governing gene expression. We have optimized the protocol of transfected cell microarrays using X-tremeGENE siRNA Transfection Reagent to transfect both expression plasmids and siRNAs, and have shown that this technology can be used to reliably detect even quantitatively minor biological effects of gene perturbations by including several technical and experimental replicates and using linear regression (ANOVA) modeling to estimate the biological effects [2] more