sample-to-sample variation, an endogenous control (GAPDH) was amplified with the target and served as an internal reference to normalize the data. Relative quantification of data from the ABI Prism 7300 Sequence Detection System was performed using the standard curve method (Applied Biosystems, User Bulletin #2; htpp://www.appliedbiosystems.com). Quantitative RT-PCR (qRT-PCR) measurements were conducted on genes to verify differences observed with microarray hybridization. These genes were selected on the basis of significant differential expression, relatively large fold changes, and the availability of primers.
